Greg Hoglund Martin Pillion

Greg Hoglund Martin Pillion
Malware Threat Analysis with HBGary Responder™ Greg Hoglund Martin Pillion

Day 1, Part 1

Introduction

Introductions Trainers Participants: introduce yourselves to the class
Greg Hoglund Martin Pillion Participants: introduce yourselves to the class Name Experience in IR & Reverse Engineering Why are you here? What would you like to learn in this class? NOTE: All trademarks referenced in this presentation are the property of their respective owners.

Class Structure Lecture for each section Demonstration
Hands-on Lab Exercises Quiz This class is focused on Incident Response and Malware Analysis with the HBGary Responder™ Professional product

Key The start of a new training section
Demo Movie that illustrates the concept Class exercise A helpful analysis hint

What You’ll Learn You will focus on reverse engineering malware programs with Responder™ You will use intelligent search terms to quickly find starting points for analysis You will learn the factors-based methodology for threat assessment

Class Materials Class DVD Responder PRO w/ Digital DNA™ Has all movies
Has slide deck Has all malware samples Responder PRO w/ Digital DNA™ Full version HASP key w/ 6 months license

Detect, Diagnose, Respond
Methodology

Detect Diagnose Respond Digital DNA™ Score Network Awareness
Security Event Management Detect IP and DNS Protocol Patterns Registry Keys File Paths Search Patterns with other solutions NIDS signatures Firewall / Blackholes Network Scans Registry Key Scans Tag machines for reimaging Malware removal

Detect Detection Triggered by some activity / observation
Immediate actions Preservation of live memory Quarantine the suspect machine(s) Image hard drive Pull the plug to contain any possible damage

Diagnose Analyze preserved memory image
Quickly identify whether a compromise indeed occurred; if so, Quickly identify Risks Suspicious activity Intruder access method(s) Capabilities and behaviors of the malware Perform disk forensics

Respond Create signatures for IDS/IPS/HIDs
Create black lists for routers to block URLs IP addresses file names, etc.

Architecture User View Digital DNA™ API to access code and data flows
RE of all Code API to access Memory Objects OS Reconstruction Physical RAM Acquisition

Projects Physical Memory Projects Static Import
Used with memory snapshots Full Windows™ OS analysis, all modules Static Import Used for stand alone binaries Used for livebins

Livebins This is the in-memory image of a running executable
With Responder™ you can extract any module from a memory snapshot These are saved to disk in livebin format

Symbol Considerations
Physical memory images offer more symbol information than livebins Livebins sometimes have “data_CALL_PTR” whereas with a physical memory snapshot these are usually labeled with actual symbol names (i.e., “CreateProcess”) In other words, you can look up the symbol on Google™ to learn more about what is going on

What to do with unknown EXE’s
Many on-disk exe’s (not livebins) have obfuscation or packing that will interfere with analysis. In this case, load them in a VM with Flypaper! Once loaded, with Flypaper, snapshot the VM Import the .vmem as a physical memory project Alas, much better results! AND, you get DDNA scores for the binaries!

What if I don’t have time?
If you don’t have VMWare installed, or don’t have time to run a VMWare session w/ the binary – there is still hope You can zip up to 50 malware programs and submit these to the HBGary Portal HBGary will automatically process all the binaries in our massive ESX server farm, and you get the DDNA results, and can also download the livebins for further analysis!

What if I have more than 50? You can upload thousands of samples at once The samples will be automatically broken into groups of fifty per job Each job will complete as a single unit of work

The HBGary Portal Click here to upload a zip
Click here to see DDNA results

Search Patterns You can have one or more wordlist files
The wordlist file has a special format String: “this is my string” (in quotes) Byte sequence: [ ] (in brackets) Strings are searched case insensitive, ASCII & Unicode

Automatic Analysis When you are in a hurry, use “Extract and Analyze all suspicious binaries” Any high score DDNA will be offered for further analysis Any rule hit from baserules.txt will be offered for further analysis

Responder Project Import
Instructor Demo Responder Project Import Movie: responder_import_project.avi

NOTES ON DEMO The instructor demo can be recorded with Camtasia. The movie should have popup text, a feature offered in Camtasia. You can pause the demo movie at any point, and narrate the movie to the class as the popup text indicates. The instructor demo should illustrate the concepts required for the following exercise, but without giving the quiz answers away.

Exercise Incident Response Infected Machine Focus Type
Steps: Once VMware is configured, and Flypaper is running a. Drag the following files to the VM window - InstDrv.exe - _root_.exe - _root_.sys b. Run _root_.exe c. Look for that process in Task Manager (look at its PID) d. Run InstDrv - load _root_.sys - start _root_.sys e. See that the process has been removed in Task Manager f. Run netstat (what flags?) and see that the port is listening to a “non-existent” PID g. Telnet to that port and verify that it is indeed listening Incident Response Infected Machine Focus Type VMware Session (StudentExercise1.vmem) Description Search for indications of compromise on a VMware image Time 30 minutes

Exercise Step by Step Answer Questions 1-3
Create a new Responder project Import “Student Exercise1.vmem” Select “parishilton.exe” for analysis Browse the following from “Project” TAB “All Open Network Sockets” Answer Questions 1-3

Exercise Questions Question 1: What suspicious TCP/UDP port is listening on the machine? Question 2: What is the name of the process bound to this suspicious port? Question 3: What is the process ID?

INSTRUCTOR ANSWERS The answer is TCP port and 31337 The process names are: 31337 is parishilton.exe we already know that is suspicious 12345 is Solitaire.EXE, not something you expect to have a socket open 3. There are two Solitaire processes, PID 128 and 1584, and parishilton.exe, PID 1152

Parishilton Networking
Exercise Recap Parishilton Networking Parishilton_network_recap.avi

NOTES ON EXERCISE RECAP
The RECAP is similar to the demo, except it shows the specific exercise the students just did, and shows how to arrive at the answer to each of the quiz questions.

Introduction to Malware Threat Factors

Goals of Assessment Rapidly determine Identify traits of the malware
Is it malicious? Does it warrant deeper investigation? Identify traits of the malware There are hundreds of traits Can be broadly grouped into six behavioral categories (“factors” )

Development Factors In what country was the malware created?
Was it professionally developed? Are there multiple versions? Is there a platform involved? Is the a toolkit involved? Are there multiple parts developed by different groups or developers?

Communication Factors
Where does it connect to on the Internet? Drop point IP addresses or DNS names Does it allow incoming connections? Does it use encryption? Does it use stego?

Command and Control Factors
How is the malware controlled by its master? Do commands come from a cutout site? What commands does it support? Sniffing, logging, file system? Attack? Poison Pill - Self-destruct? Self-uninstall / silent modes?

Installation and Deployment Factors
Does it use the registry? Does it drop any files? Does it attempt to infect other machines on the network? Does it sleep and awaken later?

Information Security Factors
Identifies the risks associated with the binary What does it steal? Does it sniff keystrokes? Can it destroy data? Can it alter or inject data? Does it download additional tools?

Defensive Factors Does it have self-defense? Does it use stealth?
Does it bypass parts of the operating system? Does it bypass virus scanners?

Computer Network Attack
Connecting to drive shares Creating large numbers of sockets (DDOS) Port scanning

This was a lecture only section, no demo or exercise.
NOTE This was a lecture only section, no demo or exercise.

Responder Overview GUI Overview

Creating a Project Two basic types Add details about the machine
Physical Memory Snapshot Live memory analysis (all running processes) Static PE Import Binary import and analysis (static binaries from disk) Add details about the machine WHY you are analyzing this machine

Importing a Snapshot File → Import → Physical Memory Snapshot
Select Snapshot File Add Details About the Snapshot Why is it of interest? Select Post-Import Options Extract and Analyze all Suspicious Binaries Generate the Malware Analysis report Same steps when importing a static binary File → Import → Import Executable Binary

The Scanning Process Import Memory Snapshot
Validate the Page Table layout and size Identify PAE/Non PAE Identify OS and Service pack Reconstruct Object Manager Rebuild EPROCESS Blocks Rebuild the VAD Tree

UI: Project Panel Shows all harvested objects
Processes, Modules, Drivers Strings, Symbols Macroscopic view of object data Allows drill-down on most objects Context-sensitive right-click menu Status icons

Responder Object Schema
Project Memory Image Hardware IDT Operating System SSDT Processes Drivers Open Files Network Socket Information Open Registry Analyzed Binary Strings Analyzed Symbols

Project type Top level folders Leaf-node folders – double click these to see details view of the folder Expandable folders – single click these to expand contents of the folder Table – double click this to see contents of table.

Drill-down via the Project Pane
The Project Pane allows you to get more details on almost any item in the report Double-clicking on items in the Project Pane typically shows detailed information about that item Provides automatic filtering Example: The SSDT can be explored in detail

Strings and Symbols Strings provide clues to origin and intention
Usually in the language of the developer Typically use descriptive variable names Symbols provide clues to behavior Export calls must be explicitly named

UI: Working Canvas Panel
Visually renders relationships and flow Control flow Data references Behavioral representation of the binary Relationships are displayed graphically No need to pore over disassembly Patterns become quickly evident

UI: Working Canvas Panel
Function head Data reference Function end

UI: Report Panel Provides a repository for observations and step-wise refinement of the analysis You can edit the description fields in the Report Panel Descriptions are inserted into the final report You can choose which report items will be included in the final report

UI: Report Panel

Report: Descriptive Text
Descriptive text can be added to the report item via In-place typing The “Edit Bookmark” feature Using “Edit Bookmark” lets you edit the bookmark name in addition to the description.

UI: Detail Panels Provide detailed information about the selected category in the Project Panel Data can be searched Data can be exported to a variety of formats PDF - XLS - CSV HTML - Image - Text RTF Panel contents can be “locked” Additional columns are available (per panel)

UI: Detail Panels Functions  SSDT Strings  IDT Symbols  Processes
Samples  Modules Files  Drivers Registry  Network

Using Detail Panels The detail panels can be sorted by any column
A quick way to find the hooked SSDT entries is to sort by target module

Leaf-node folders: double-click these to see the detail panel of the folder

Right click on header to get column chooser

Search the Detail Panel, which filters the panel’s contents to only those entries that match the search criteria

1. Lock the window after filtering
2. Double click the “All Open Registry Keys” folder again. Since the default window (the Registry Panel) is locked, a new (unfiltered) Registry View window is created. You can lock as many as you choose

Context-Sensitive Actions
Every panel has a right-click context menu Menu choices based on selected object(s) Most common options Send to report: creates entry in the Report Pane for the selected item Google™ Text Search: uses Google™ search engine to find Internet references to the selected item Google™ Code Search: uses Google™ search engine to find source code that uses the selected item (typically a string or symbol)

Student should be able to drive now
Notes Student should be able to drive now

Exercise TODO – verify this works Communications Factors Focus Type
Interactive Analysis Description Use graphing techniques to quickly isolate the Communications Factors associated with both a memory image and a captured piece of malware. Time 25 minutes

Exercise Create a new project (Physical Memory Snapshot)
Import memory image \Student Exercise 7\Student Exercise 7 CyberEspionage case.vmem Answer the set of questions in the handout (“Exercise 7 Questions”)

Review: Exercise Ipod.raw.exe Identify Communication Factors
Identify if there are any hard coded IP’s Identify any domain names Identify 3 network protocols used Identify any addresses Identify Installation and Deployment Factors Registry locations to survive a reboot Dropped Files Taskdir.exe Identify Communication Factors Identify if there are any hard coded IPs Identify Installation and Deployment Factors Identify 5 network related strings & API calls

Review: Exercise Seigxbsg.exe: Identify Communication Factors
Identify if there are any hard coded IP’s Identify any domain names Identify Installation and Deployment Factors Registry locations to survive a reboot Dropped Files Identify any Defensive Factors Taskdir.dll:

Day 1, Part 2

Directories, Files, and Downloads
Basic Installation and Deployment Factors

Why I&D matters Knowing how it installs can help you:
Design a cleanup script Scan for other infected machines Detect variants of the same malware

Objects of Interest Files, file extensions, paths .INI files
Find/Next type loops, wildcards (“*.*”) Command line parameters Registry keys TEMP directory Checking for mutexes Sometimes used so they don’t infect twice

Directory and File Creation
Start with these strings & symbols: CreateDirectory ExpandEnvironmentStrings “%ProgramFiles%” “%SystemRoot%” File extensions “.exe” “.dll” “.sys”

Starting points for Directory and File Creation
CreateDirectory GetSystemDirectory CreateFile DeleteFile CopyFile OpenFile ExpandEnvironmentStrings %PROGRAM FILES% %SYSTEMROOT% C:\ .EXE .DLL .SYS .INI .INF .BAT *.* \\ (double backslash) MoveFile \\TEMP WINDOWS SYSTEM32 cmd /c del del %s GetTempPath

Directory Creation CreateDirectory, CreateDirectoryEx
mkdir, wmkdir, _tmkdir _creat system(“mkdir … system(“md …

Environment Variables
ExpandEnvironmentString GetEnvironmentVariable getenv, putenv

Common environment variables
%ALLUSERSPROFILE% C:\Documents and Settings\All Users %APPDATA% C:\Documents and Settings\{username}\Application Data %COMPUTERNAME% {computername} %COMSPEC% C:\Windows\System32\cmd.exe %HOMEDRIVE% C: %HOMEPATH% \Documents and Settings\{username} %PATH% C:\Windows\System32\;C:\Windows\;C:\Windows\System32\Wbem %PATHEXT% .COM; .EXE; .BAT; .CMD; .VBS; .VBE; .JS ; .WSF; .WSH %PROGRAMFILES% Directory containing program files, usually C:\Program Files %PROMPT% Code for current command prompt format. Code is usually $P$G %SYSTEMDRIVE% The drive containing the Windows XP root directory, usually C: %SYSTEMROOT% The Windows XP root directory, usually C:\Windows %TEMP% and %TMP% C:\DOCUME~1\{username}\LOCALS~1\Temp %USERNAME% {username} %USERPROFILE% C:\Documents and Settings\{username} %WINDIR% C:\Windows %DATE% Current date in the format determined by the Date command %TIME% Current time in the format determined by the Time command %CD% Current directory with its full path %ERRORLEVEL% Number defining exit status of a previous command or program %RANDOM% Random number between 0 and 32767

Special Folder Locations
SHGetSpecialFolderLocation CSIDL_ADMINTOOLS (FOLDERID_AdminTools) The file system directory that is used to store administrative tools for an individual user. CSIDL_ALTSTARTUP (FOLDERID_Startup) The file system directory that corresponds to the user's nonlocalized Startup program group. CSIDL_APPDATA (FOLDERID_RoamingAppData) C:\Documents and Settings\username\Application Data. CSIDL_BITBUCKET (FOLDERID_RecycleBinFolder) The virtual folder that contains the objects in the user's Recycle Bin. CSIDL_CDBURN_AREA (FOLDERID_CDBurning) C:\Documents and Settings\username\Local Settings\Application Data\Microsoft\CD Burning. Use MSDN to lookup all the possible values, there is a long list…

Shell32 API SHELL32.DLL SHGetPathFromIDList SHBrowseForFolder
SHGetSpecialFolderLocation

Internet Downloads The WININET.DLL API winsock API InternetOpenFile
InternetReadFile InternetOpenURL InternetConnect socket WSASocket connect WSAConnect … Addresses, URL, and web requests www .com HTTP/1.0 Content-Type

Malware Boot Registry Keys
Registry API Try searching… RegCreateKey RegOpenKey “CurrentControlSet” “CurrentVersion” “SOFTWARE” (all caps) Common registry keys to survive reboot HKLM\Software\SOFTWARE\Microsoft\Windows\CurrentVersion\Run HKCU\Software\SOFTWARE\Microsoft\Windows\CurrentVersion\Run HKCU\Software\Microsoft\Windows\CurrentVersion\RunServicesOnce HKLM\Software\Microsoft\Windows\CurrentVersion\RunServicesOnce HKCU\Software\Microsoft\Windows\CurrentVersion\RunServices HKLM\Software\Microsoft\Windows\CurrentVersion\RunServices HKLM\Software\Microsoft\Windows\CurrentVersion\RunOnceEx HKLM\SYSTEM\CurrentControlSet\Services\{Service Name}

Basic Installation Factors
DEMO Basic Installation Factors Movie: huntpeck_install_factors.avi

Exercise TODO – Review this works Installation Factors Focus Livebin
Paris hilton exe Description Use graphing techniques to quickly isolate installation behavior Time 15 minutes

Import memory image \Vmem\Student Exercise1.vmem Search the strings in memory of ParisHilton Go to search window, enter “command” Find “exefile\shell\open\command” Drop string onto canvas, grow up Answer the set of questions

Screen Shot

Exercise What is the purpose of exefile\shell\open\command?
What is the filename being used? What file is it replacing? What file looks like it is being deleted? What file looks like it is being copied? BONUS –What does that accomplish? What file is this being copied from?

Instructor Questions and Answers
What is the purpose of exefile\shell\open\command? - To launch an exe every time another exe is launched What is the filename being used? - wmmiexe.exe What file is it replacing? -wmiexe.exe What file looks like it is being deleted? wmiexe.exe What file looks like it is being copied? explorer.exe BONUS –What does that achieve? If explorer.exe is put to What file is this being copied from? Zzz.tmp

Exercise Installation Factors Focus Livebin Inhold_toolbar Description
Use graphing techniques to quickly isolate installation behavior of inhold.toolbar Time 25 minutes

Exercise, Step by Step Start Responder and create a new project (Static Import) titled “inhold.1” Import the inhold.1.mapped.livebin Show symbols and filter for “CreateDirectory” Graph region around CreateDirectory Answer Questions 1-2 Look for the local path that is being used to store files Answer Questions 3-4 Discover how the files are being downloaded Answer Questions 5-6 Organize and flatten your graph Produce a concise RTF report with this information Continue on next slide…

Exercise Questions Questions What paths and URL’s stand out?
What registry key is being created What environment string is being queried? What directory is being created locally? What API call is used to download files from ‘Net onto the computer? What are the remote and local names of the files, respectively

Instructor Answers What paths and URL’s stand out? Two URLs for InholdBar22.exe Uninstall22.exe /InholdBar/ What registry key is being created SOFTWARE /InholdBar What environment string is being queried? %ProgramFiles% What directory is being created locally? Program Files/InholdBar What API call is used to download files from ‘Net onto the computer? URLDownloadToFile What are the remote and local names of the files, respectively Remote InholdBar22 stores locally as InholdBar.exe Remote uninstall22.exe stores locally as uninstall.exe

Basic Installation Factors
Exercise Recap Basic Installation Factors Movie: 5_min_install_factors.avi

Notes Student has analyzed a fairly decent malware sample, found network URL’s that can be used for firewall and IDS, and knows where its installed on the machine, and has a good chance of being able to uninstall it

Reconstructing string operations
Format Strings Reconstructing string operations

Format strings Format strings are important to understand because you will encounter them so often.

Basic format strings %s – a string (also %S) %c – a character
%d – a number (also %i) %x – a number in hex (also %02x, %08X, etc) %f – a number in float %l – a number (long) (also %ul) %% - a percent character (there are many variants of the above)

Functions that use format strings
printf sprintf fprintf snprintf swprintf wsprintf vsprintf … variants of the above … %s %c %f %i %d %l %lu … etc …

Path Creation

GetSystemDirectory This is used to place files in the windows system32 directory If within a subroutine, grow up to see what kind of arguments are passed in Target: CreateRemoteThread livebin

Search registry for this
Construction of a string under the Services key means this file could be registered as a service. Target: CreateRemoteThread livebin

Creates a directory in the Program Files directory.
Target: inhold toolbar

Call setup 4 3 2 1 The args to a format string are almost always pushed directly before the format string in disassembly (reverse order) 1 2 3 4

%d argument to format string
DEMO %d argument to format string Movie: res_url.avi

Batch Files %1, %2, %3 etc Used to indicate arguments passed to a batch file Look for .bat extension in strings

Using format strings as hints
It is very likely that esi+4 stores a pointer to the nick used in IRC channel

IP Address Format String
DEMO IP Address Format String Movie: format_string_ip_address.avi

Exercise Installation and Deployment Factors Focus VMEM VIRUS.VMEM
Description Use graphing techniques to quickly isolate the Installation and Deployment Factors associated with both a memory image and a packed piece of malware. Time 25 minutes

Exercise Step by Step Create Physical Memory Snapshot Project called “virus.exe” Import memory image Analyze Virus.exe exe Hid_evr2.sys Answer questions 1-5

Exercise Questions Questions
Identify the registry locations used to survive reboot Is there anything peculiar about the EXE’s name that is registered to survive reboot? How does the malware choose the numerical filename? What directory does the numeric EXE get placed in What files, processes, drivers are dropped from Virus.exe?

Identify the registry locations used to survive reboot "Software\Microsoft\Windows\CurrentVersion\Run“ Is there anything peculiar about the EXE’s name that is registered to survive reboot? "\%lu.exe“ – it’s always a number.EXE How does the malware choose the numerical filename? Uses GetTickCount What directory does the numeric EXE get placed in The windows directory What files, processes, drivers are dropped from Virus.exe? exe Trust.exe

Exercise Recap Movie: virus.exe.filename.avi

Droppers & Multi-stage execution
Installation and Deployment Factors

What is a Dropper? Malware is delivered in steps
Dropper is initial downloaded package Can be a trojan or embedded exploit The dropper carries the malware in a payload Once “dropped”, the dropper decompresses and executes a secondary payload

Steps in Malware Deployment
Dropper Embedded Resource Decompressed to Disk Embedded Resource Embedded Resource is Launched as an EXE

Multi-Stage Execution
Child Process Spawning CreateProcess ShellExecute Creating Files WriteFile CopyFile

Launching External Processes
Typical APIs used to launch processes RunDLL32.exe Shell32.dll Control_RunDLL Can be used to run a shell script Command line shows the path to the file on disk

Starting points for Process Creation
CreateProcess Rundll32.exe cmd.exe cmd /c command.com /c %s ShellExec ShellExecute ShellExecuteA WinExec Shell32.DLL exec execve system

Cleanup using BAT files
@echo off :%s del %%1 if exist %%1 goto %s rem %s"

CreateProcess w/ cmd.exe
DEMO CreateProcess w/ cmd.exe Movie: shell_createprocess.avi

Exercise Installation and Deployment Factors Focus LIVEBIN
inhold toolbar Description Recover ShellExecute arguments used within inhold toolbar Time 25 minutes

Exercise Step by Step Open your inhold toolbar livebin project
Search symbols for “exec” Graph the region around ShellExecuteA Use the Code View to reconstruct the arguments being supplied to ShellExecuteA Answer questions 1-5

Exercise: Questions What does the lpOperation argument do for ShellExecuteA ? What action is being performed by inhold toolbar? What does inhold toolbar supply as the lpFile parameter? What environment variable is used to construct the file path? What is the path to the executable being launched?

What does the lpOperation argument do for ShellExecuteA ? Defines the action to be performed What action is being performed by inhold toolbar? “open” What does inhold toolbar supply as the lpFile parameter? A file path to an executable What environment variable is used to construct the file path? %ProgramFiles% What is the path to the executable being launced? Program Files \ InHoldBar \ InHoldBar.exe

RECAP Shell Execution Movie: shell_exec.avi

Multi-Stage Execution
Resource Extraction OpenResource Use of temporary directory GetTempDirectory Consult execution history in Flypaper

Starting points for Resource Extraction
FindResource SizeOfResource Possible embedded kernel drivers PsCreateSystemThread \\DosDevices .sys drivers IoCreateSymbolicLink IoDeleteSymbolicLink IoCreateDevice IoDeleteDevice KeInitialize SpinLock ObReferenceObjectByHandle

When using flypaper, all of the child processes will be available in the memory snapshot. Examine them all and compare them to one another. MEP Target: MEP

Notice how the copy of the process has more loaded modules Target: MEP

Compare Copies Compare the secondary execution against the first one
Different number of loaded modules The one with more modules implies that it has progressed farther in the execution lifetime Compare strings and symbols of both copies There may be additional unpacking in the secondary copy

MEP Target: MEP

RunDLL32

RunDLL32 Executes a subroutine exported from a DLL
RUNDLL32.EXE <dllname>,<entrypoint> <optional arguments> Example: RUNDLL32.EXE SHELL32.DLL,Control_RunDLL desk.cpl,,0 void CALLBACK EntryPoint( HWND hwnd, HINSTANCE hinst, LPSTR lpszCmdLine, int nCmdShow);

This was a lecture only section, no demo or exercise
NOTE This was a lecture only section, no demo or exercise

Bundled Kernel Drivers

DevIoControl Method of communication between usermode and kernelmode
See hide_evr.sys

IoCompleteRequest Called when a driver has finished processing an IRP
Thus, can be used as a guidepost to find IO callback functions (IoCompletion routines) Open, Close, Read, Write, IOControl, etc. May be used as IofCompleteRequest Little ‘f’ means fastcall interface

ExAllocatePoolWithTag
When pool tags are used, the allocations made by the driver can be tracked See hide_evr.sys

Pool Tags Used in kernel mode memory allocation
Track buffers passed thru DeviceIoControl

Pool Tag Buffers Demo finding pool tag ‘Wdm ‘ in hide_evr.sys

Day 1, Part 3

DLL and Thread Injection

Process Enumeration For any process to write to another process, it needs a handle to the target To get a handle to a process, the process must be located from the list of all processes Process enumeration primarily occurs using ToolHelp API NtQuerySystemInformation( ) Undocumented API

DLL & Thread Injection Look for ToolHelp library usage
This will be used to enumerate running processes when finding one to inject into Look for CreateRemoteThread This is used to inject the code that will load the injected DLL Look for EnableDebug or AdjustPriv The process will need certain access rights to be able to perform the injection

DLL Injection Injected DLLs stand out clearly if they use
Non-standard paths Unusual or odd-sounding names

Strings ending in .dll All modules

Remote Threads A remote thread is created in a second process, not part of the first process A remote thread is typically used to inject a DLL into another process, but not always A remote thread can also operate without a DLL injection This is a more advanced technique

Clear indication of process injection
MEP Clear indication of process injection

Page Protections In order to inject against another process, memory protections will need to be unlocked This is done via the VirtualQuery API Use “Google™ Text Search” to get the API arguments

Searching Google™ on each of the
MEP Searching Google™ on each of the symbols clearly indicates they all can access a remote process.

Starting points for DLL and Thread Injection
CreateRemoteThread OpenProcess VirtualAlloc WriteProcessMemory WaitForSingleObject explorer.exe SeDebugPrivilege CreateToolhelp32Snapshot CreateEvent Process32First Process32Next Module32First Module32Next

DEMO Create Remote Thread Movie: create_remote_thread_RR.avi

Exercise Installation and Deployment Factors Focus LIVEBIN
CreateRemoteThread Description What is being injected into the remote process? Time 25 minutes

Exercise Step by Step Open livebin CreateRemoteThread
Search symbols for “remote” Graph the region around CreateRemoteThread Answer questions 1-5

Exercise: Questions What is WriteProcessMemory being used for
What is being written to the remote process? What start address is being used for the remote thread? How does the malware determine what start address to use? What does the remote thread do?

What is WriteProcessMemory being used for? -- it writes a string to the remote process What is being written to the remote process? -- the path “C:\WINDOWS\TEMP\~222e8c.~~~” What start address is being used for the remote thread? -- The address of “LoadLibrary” How does the malware determine what start address to use? -- uses GetProcAddress on kernel32 What does the remote thread do? -- it loads “C:\WINDOWS\TEMP\~222e8c.~~~” as a DLL

Recap Create Remote Thread Movie: create_remote_thread_RR2.avi

Registry Keys Installation and Deployment Factors

Registry Key Creation Start with these: Search symbols for “reg”
RegOpenKey RegCreateKey “CurrentControlSet” “CurrentVersion” “SOFTWARE” (all caps)

Starting points for Registry Modification
RegCreateKey RegOpenKey .REG regedit RegCloseKey CreateService DeleteService OpenSCManager ServiceMain ServiceDll StartService CurrentControlSet SOFTWARE \\ (double backslash) CurrentVersion

Malware Boot Registry Keys
Massive numbers of registry keys (too numerous to list here) See “Autoruns” See “MAP” Plug-in

The Run Keys HKLM\Software\SOFTWARE\Microsoft\Windows\CurrentVersion\Run HKCU\Software\SOFTWARE\Microsoft\Windows\CurrentVersion\Run HKLM\Software\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run HKCU\Software\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\Explorer\Run HKCU\Software\Microsoft\Windows\CurrentVersion\RunServicesOnce HKLM\Software\Microsoft\Windows\CurrentVersion\RunServicesOnce HKCU\Software\Microsoft\Windows\CurrentVersion\RunServices HKLM\Software\Microsoft\Windows\CurrentVersion\RunServices HKLM\Software\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce HKCU\Software\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce HKLM\Software\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce\Setup HKCU\Software\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce\Setup HKLM\Software\Microsoft\Windows\CurrentVersion\RunOnceEx HKCU\Software\Microsoft\Windows NT\CurrentVersion\Windows\Load

User Init HKLM\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\Userinit The above key takes a comma delimited list of programs to execute. Malware may install additional programs, or even replace the existing userinit.exe with a trojan version. The normal location for userinit.exe will be something like C:\WINDOWS\system32\userinit.exe (the windows install directory will be system specific). Any strange looking path or additional executables should be examined in detail.

Creating Services Creating a service via API calls simply creates registry keys under the hood CreateService One alternative way to load a device driver is the SystemLoadAndCallImage method ZwSetSystemInformation api call

HKLM\SYSTEM\CurrentControlSet\Services\{Service Name}
For any given service, there may be a value called ImagePath that will indicate the path to the file that implements the service. If the file in question ends in “.sys” there is a good chance that it’s a kernel mode driver. To be sure you can check the Type value: Type Description 1 Kernel mode driver 2 File system driver 4 Adapter Arguments 8 File system service 16 Win32 program that runs as it's own process 32 Win32 program that shares a process w/ other services (think services.exe) The Start value can tell you when the service is started: 0 Boot, very early during startup 1 System, after Boot, but still while booting Windows 2 Automatic, after System, but still while booting Windows 3 Manual, doesn't run unless the user or another program starts it 4 Disabled

DEMO Registry Keys Movie: disable_logoff_startmenu.avi

Exercise Installation Factors Focus vmem Beizhu_2 Description
Use graphing techniques to quickly isolate temporary path used with runonce key Time 25 minutes

Exercise, Step by Step Start Responder and create/open project for “beizhu_2.vmem” Import beizhu_2.vmem (if creating new project) Find and extract malware.exe Search for “\” (backslash) in strings view, drop registry keys to canvas Look for the value being used with the RunOnce key Try to determine what the value used with the RunOnce key is used for Hint: look for a temporary path Answer Questions 1-6

Exercise Questions Questions
What value is being used under the RunOnce key? What command is being written to the cleanup value? What path is being passed to the DelNodeRunDLL32 API call? What path is being prepended in front of advpack.dll? Any ideas on what this value is being used for? Bonus: How is the temp path generated?

What value is being used under the RunOnce key? wextract_cleanup0
Instructor Answers What value is being used under the RunOnce key? wextract_cleanup0 What command is being written to the cleanup value? rundll32.exe %sadvpack.dll,DelNodeRunDLL32 "%s“ What path is being passed to the DelNodeRunDLL32 API call? C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp\IXP000.TMP\ What path is being prepended in front of advpack.dll? The system directory, obtained from GetSystemDirectory Any ideas on what this value is being used for? Deleting files on restart How is the temp path generated? Appended with a number, using "IXP%03d.TMP"

Registry RunOnce Value
Exercise Recap Registry RunOnce Value Movie: BEIHZU_RunOnce.avi

Shell Extensions Installation and Deployment Factors

The Shell Malware can install one or more DLL’s on the system that are tied into your shell, menu’s, mouseclicks, actions, browsing – almost anything you can imagine

Starting points for detecting Shell Injection
ShellEx Classes\Folder Classes\CSLID InProcServer32 shell\open shell\open\command exefile batfile comfile ddeexec

Shell Column Handlers HKCR\Software\Classes\Folder\Shellex\ColumnHandlers\{GUID} To find the actual program that is handling the column extension, you need to locate the GUID elsewhere in the registry. It will likely be located under the Classes folder: HKLM\SOFTWARE\Classes\CLSID\{GUID} If you check the InProcServer32 subkey, you will find a path to the DLL that is implementing the column extension.

Shell Open commands Malware can register itself as the handler for certain file extension types, controlled from the HKEY_CLASSES_ROOT (HKCR) folder and the HKLM\Software\Classes folder. There are many file extension types under these folders, but the following are well known hook points for malware: HKCR\batfile\shell\open\command HKCR\comfile\shell\open\command HKCR\exefile\shell\open\command HKLM\Software\Classes\batfile\shell\open\command HKLM\Software\Classes\comfile\shell\open\command HKLM\Software\Classes\exefile\shell\open\command The default value for the command key should be "%1" %*, but malware can modify the entry to contain something like “malware.exe” “%1” %*, causing the malware program to execute if someone double-click launches one of the infected file extensions.

Command and DDE Exec HKCU\Software\Classes\<some registered extension/path>\shell\<path>\ddeexec\ These keys have the same problems as described above for Shell Open Commands. In addition, you may notice a neighboring command key, which can also be altered or infected by malware. HKCU\Software\Classes\<some registered extension/path>\shell\<path>\command\

Browser Extensions Installation and Deployment Factors

The Browser Malware can install one or more DLL’s that are tied into your browser, browsing events, keylogging, user interface, and more

Starting points for detecting Browser Injection
\Internet Explorer \Extensions \Explorer Bars \Script \Exec \Browser Helper Objects InprocServer32 URLSearchHook Implemented Categories\ { C } { C } {4D5C8C2A-D075-11d0-B416-00C04FB90376} InitPropertyBag\Url

Browser Extensions This includes adding menu’s and shortcuts, additional toolbars, explorer bars, and browser helper objects. A simple way to add an additional menu item or button is to register a GUID under the following key: HKCU\Software\Microsoft\Internet Explorer\Extensions\{GUID} HKLM\Software\Microsoft\Internet Explorer\Extensions\{GUID} You may also find subkeys that path to an executable or script: HKLM\Software\Microsoft\Internet Explorer\Extensions\{GUID}\Script HKLM\Software\Microsoft\Internet Explorer\Extensions\{GUID}\Exec The values stored under these keys may lead you to a program that implements whatever command is indicated by the menu item or button.

Browser Helper Objects
The term BHO is used loosely in the security community, and you may run across the term BHO being used to describe any malware that extends the browser – even if the malware is not specifically a BHO. Just remember that a BHO is just one of many ways malware can inject into the browser. A BHO is registered by adding a GUID to the following registry key: HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer \Browser Helper Objects\{GUID} Similar to all the other GUID based extensions, the GUID can be looked up elsewhere in the registry to determine which DLL handles it. It will likely be found in a location like: HKCR\CLSID\{GUID} And, as usual, the InprocServer32 key will reveal which DLL is used to implement the BHO.

Day 2, Part 1

Browser Hijacking and Bank Info Stealers
Information Security Factor

Browser Extensions UrlSearchHooks Extensions Browser Helper Objects

Filter and Grab Most BHO’s of this type have special search patterns that are very specific to a known banking site Once this pattern is “triggered”, the BHO injects, intercepts, or copies data

Injecting HTML Injection into an already displayed page
objectReference.insertAdjacentText(position, textstring) objectReference.insertAdjacentHTML(position, textstring) position: where to put the injected text “beforeBegin”: immediately before the element, outside the element's enclosing tags (not affected by any formatting the element generates). “afterBegin”: just after the opening tag of the element “beforeEnd”: just before the closing tag of the element “afterEnd”: immediately after the closing tag of the element (not affected by any formatting the element generates). text: the text to insert

HTML Injection BHO has injected this HTML into the live banking page
This screenshot provided by threatexpert.com

Scramble Pads Graphical representation of numbers or letters that the user clicks on instead of typing keys Intent is to bypass keyloggers As the data is processed by the browser, the BHO can intercept the data, irrespective of keyboard or mouse

Virtual Keyboards Even though the virtual keyboard bypasses the actual keyboard, the cleartext username and password details are stored all over in the browser RAM BHO’s can scan for the cleartext results

Transaction Authentication Number (TAN)
2-factor authentication, basically a one-time use password Used to authenticate a bank transaction Small lists of TAN’s are given to banking client for one-time use “TAN Grabber” BHO’s will steal correct TAN when its submitted to bank and substitute it with a fake, the user does not realize the transaction failed The valid TAN is then used to make a fraudulent transaction

Keylogging,Passwords, and Data Theft

DEMO Information Security Factors

Goal: Rapidly identify if the malware can steal information Passwords Keystrokes Login credentials Intellectual property/secrets

What is Being Stolen? File scans Keystrokes Usernames and passwords
Screen shots / screen scraping

Recently Used Passwords
Common Targets GUIDs for Saved Passwords Outlook Internet Explorer Pstore.dll

File Searching Used for a variety of reasons
Locate intellectual property Locate password files Search out DLL’s and executables Find files to infect Cleanup temporary files after installation

File Searching Typical API Calls Strings FindFirst( ) FindNext( )
Wildcards File Extensions

Target: soysauce

Keystroke Logging Windows Message Hooking Polling Interrupt Hooking
IRP hooking 8042 Keyboard Controller Port 60, 64

DEMO Keylogging Movie: keylogging_windowshook.avi

Exercise Keylogging Focus LIVEBIN keylogger.1.mapped.livebin
Description How is the malware sniffing keystrokes? Time 25 minutes

Exercise Step by Step Open/create project for livebin keylogger.1.mapped.livebin Search symbols for “key” Graph the region around GetAsyncKeyState and relabel the data_CALL_PTR used with it Find the code that actually calls GetAsyncKeyState Try to graph the key sniffing loop Try to find the keytable that is used by the sniffing loop Answer questions 1-4

Exercise: Questions How many places call GetAsyncKeyState?
Are there any filenames that might be a keylog file? How many places call GetAsyncKeyState? How many keys can be checked at a time? Where is the table of keycodes (what address)?

Are there any filenames that might be a keylog file? “keys.txt” How many places call GetAsyncKeyState? just one, loc_0040A692 How many keys can be checked at a time? Just one, each key has to be tested one at a time Where is the table of keycodes (what address)? 0x42F1EC

Password File Searching
DEMO Password File Searching Movie: rdp_password_sniffer.avi

NOTE This following exercise should reinforce their previous work with format strings, while introducing FindFirstFile

Exercise File Searching Focus LIVEBIN FindFile.1.mapped.livebin
Description What DLL naming scheme is being used by the malware? Time 25 minutes

Exercise Step by Step Open/create project for livebin findfile.1.mapped.livebin Search symbols for “find” Graph the region around FindFirstFile and FindNextFile Answer questions 1-4

Exercise: Questions What is the filename wildcard being used?
What is the malware searching for on the filesystem? One or more DLL’s What is the filename wildcard being used? “sh” followed by a number, then “*.dll” What directory is the malware searching in? The system directory Can you recover a specific DLL name? sh9025.dll

What is the malware searching for on the filesystem? - One or more DLL’s What is the filename wildcard being used? - “sh” followed by a number, then “*.dll” What directory is the malware searching in? -The system directory Can you recover a specific DLL name? - sh9025.dll

Recap File Searching Movie: findfile_dll.avi

Screenscrapers and Audio Bugs

Screenshots BitBlt, screenshot methods

INSERT EXAMPLE OF SCREEN SCRAPER
TODO

Communications Factor
Data Exfiltration Communications Factor

Network Communications
WS2_32.DLL WINET_XXX functions Wsock32.dll TCP/UDP Hard-coded IP addresses and web addresses

WSAStartup Initiates use of the Winsock DLL by a process
Must be the first Windows Sockets function called by an application or DLL Use it to determine the order of operations

WSAGetLastError Returns the error status for the last Windows Sockets operation that failed Communications Factor Can be used to detect error-handler code vs. continued execution code Development Factor Showing how well the developer checks error codes is an indication of their formal training and programming skill

Winsock TCP / UDP Functions
TCP (socket-based) recv WSARecv UDP (datagram-based) recvfrom WSARecvFrom

Imported functions from winsock
recvfrom is UDP

Protocols strings SMTP HTTP POST / GET requests

Hosts and Addresses inet_ntoa inet_addr
converts IP to a string (dynamically) inet_addr converts readable IP to number (dynamically)

Detecting the Protocol
By examining the arguments that are pushed on the stack prior to the “socket” call, you can detect which protocol is being used 1,3,2 versus 6,1,2

Starting points for COMS factors
InternetOpen InternetOpenURL InternetReadFile InternetCloseHandle ftp:// .asp

Exercise Communications Factors Focus Type Interactive Analysis
Description Use graphing techniques to quickly isolate all the coms factors in the realmBOT malware Time 25 minutes

Start Responder and create a new project (Static Import) titled “realmbot.1”
Import the realmbot.mapped.livebin Use graph techniques to find all the callers of socket Use cheat sheet to determine if sockets are UDP or TCP Answer Questions 1-2 Continue on next slide… Questions How many locations make sockets, and how many of each type are there? Is there anything inconsistent about how the malware author creates the UDP and TCP sockets?

Exercise continued… Use graph techniques to build a single layer for each code region that makes a socket Look for information that reveals what each code region is doing Answer Questions 1-3 Build a final graph with each COMS factor in it’s own layer Generate a final report in RTF format Questions What protocols are being used by the code regions? Do any of the code regions run as a server and listen for incoming connection? What other features do the code regions appear to offer (computer network attack)?

Instructor Answers How many locations make sockets, and how many of each type are there? 7 sockets 2 UDP 5 TCP Is there anything inconsistent about how the malware author creates the UDP and TCP sockets? The author uses IPPROTO_IP sometimes, and IPPROTO_UDP or TCP sometimes These provide the same functionality, but are two different styles Maybe cut and paste code What protocols are being used by the code regions? IDENT This is a TCP IRC This is TCP SMTP / TFTP This is UDP

Instructor Answers Do any of the code regions run as a server and listen for incoming connection? The IDENT code listens for incoming TCP connections Bonus: which port does it listen on TCP port 113 What other features do the code regions appear to offer (computer network attack)? UDP pings Bonus: why did the malware author use UDP to ping? ICMP may be blocked by Windows firewall TCP Port scanning Bonus: traditional connect scanning, which is slow Port Redirection Represents path into internal network behind NAT

Exercise Recap Callers of socket Callers_to_socket.avi

Exercise Communications Factors Focus Type Interactive Analysis
Description Use graphing techniques to quickly isolate the Communications Factors associated with both a memory image and a captured piece of malware. Time 25 minutes

Import memory image \Student Exercise 7\Student Exercise 7 CyberEspionage case.vmem Answer the set of questions in the handout (“Exercise 7 Questions”)

Review: Exercise Ipod.raw.exe Identify Communication Factors
Identify if there are any hard coded IP’s Identify any domain names Identify 3 network protocols used Identify any addresses Identify Installation and Deployment Factors Registry locations to survive a reboot Dropped Files Taskdir.exe Identify Communication Factors Identify if there are any hard coded IPs Identify Installation and Deployment Factors Identify 5 network related strings & API calls

Review: Exercise Seigxbsg.exe: Identify Communication Factors
Identify if there are any hard coded IP’s Identify any domain names Identify Installation and Deployment Factors Registry locations to survive a reboot Dropped Files Identify any Defensive Factors Taskdir.dll: S_65: Identify if there are any hard coded IPs Dropped Files

Day 2, Part 2

Loops Most designs will have a loop in the code that goes around and around getting packets There are many variations of this, but they all follow this general design Identifying the Communications Factors requires you to discover (and graph) this loop

Loops Most communications control flow is looped
Multiple outbound connections Periodic check-in DDOS attack, large volume of sockets Multiple inbound connections (server)

Loops Outer loop Inner loop
Typically is large Calls down into specific behaviors Usually links many different kinds of behaviors together Example: the outer loop may grab packets from the network and feed them to the Command and Control code Inner loop Usually small and only calls into one specific behavior Example: code that reads a file looking for passwords Both kinds of loops help you understand the malware but in different ways

Program continues around the outer loop until shutdown.
Program Start Outer Loop At this point in the code, the outer loop makes a branching decision and enters the inner loop. The program can go around the inner loop many times before coming back out. Once the program leaves the inner loop, it continues along the outer loop. Inner loops can branch into even deeper inner loops. Nested Inner Loops Inner Loop Inner Loop

Loops: Timers and Triggers
Most loops have some sort of pause; otherwise, they would consume 100% CPU Timer-based loop: usually uses the Sleep() API to wait a specific number of milliseconds between each iteration Trigger-based loop: responds to some external stimulus via a callback or a blocking call

Loops: Blocking Call Blocking call: Function call that effectively pauses until some event occurs Can have a “timeout” parameter, and will continue execution after the timeout if the event doesn’t occur In these cases, the return value from the call is usually checked to determine if the timeout expired or the event occurred (to tell the difference) A very common blocking call is “recv”, the function that gets packets from the network The “recv” function will pause until a packet arrives

Software stops here and waits for a signal.
Only after the signal has fired does the software enter the inner loop.

A bunch of functions are called all in a row
A bunch of functions are called all in a row. These functions are the main body of the software’s capabilities. A very basic Sleep architecture. After Sleep returns, program goes back to top of loop and runs again. Sleep anywhere from a few seconds to minutes or even hours

Wait for network packet.
Check to see if entire command has arrived. Continues only after complete command has arrived. Read packet from buffer. Process the command

d Sleep if connection could not be made
Continue if web connection made Attempt outbound web connection Send HTTP request Check to see if entire webpage has been read. Read webpage from network. Continue after entire webpage has been read Parse webpage for secret commands

Callback Functions Callback: Function that is called by an external component Not typically represented as a loop in the code Can be a timer, or an event such as a packet arriving Callbacks are “registered”, usually at program startup The actual callback function is usually not in the same place as the “registration” step, making these more difficult to identify

DEMO Loops Movie: file_delete_loop.avi

Exercise Defensive Factors Focus Type Interactive Analysis Description
Use graphing techniques to quickly isolate the cleanup routine used by molebox packer Time 25 minutes

Start Responder and create a new project (Static Import) titled “molebox.1”
Import the molebox.1.mapped.livebin Show strings and filter for “FindFirstFile” Grow the graph up and down and find the data_CALL_PTR associated with “FindFirstFile” Use graph techniques to find other functions and relabel the call pointers Answer Question 1 Continue on next slide… Questions Which function is performing the equivalent of a GetProcAddress?

Use graph and layer techniques to grow up from the call pointers
Delete File Sleep GetCurrentDirectory Others… Try to connect all of the graph regions together into one graph, organize and flatten it Try to relabel the blocks Identify success and failure conditions after an API call Identify any sleeps Identify any loops Answer Questions 2-6 Identify the location which stores the filename that is being searched/deleted Answer Questions 7-9 Continue on next slide…

Questions Does the program attempt to delete more than once? Can it delete multiple different files? How long does the program sleep between delete attempts If the first attempt at finding files with FindFirstFile finds nothing, does the program enter the loop at all? Which directory does the program search for files to delete? What is the address of the filename pattern that is being deleted? What is the file pattern that is being used to search for files to delete? Bonus: did you find any other filename strings that match the pattern?

Instructor Answers Does the program attempt to delete more than once? Yes, it loops attempting multiple delete attempts Can it delete multiple different files? It uses FindFirstFile which supports a wildcard, so yes it can How long does the program sleep between delete attempts 500 ms If the first attempt at finding files with FindFirstFile finds nothing, does the program enter the loop at all? No, it does not enter the loop in this case Which directgory does the program search for files to delete? The current working directory

Instructor Answers What is the address of the filename pattern that is being deleted? Data_0047B914 What is the file pattern that is being used to search for files to delete? Bonus: did you find any other filename strings that match the pattern? There are a few other strings like this, but without the * wildcard

Molebox Cleanup Routine
Exercise Recap Molebox Cleanup Routine Molebox_vs_responder.1.avi

Computer Network Attack
DDOS Attack Computer Network Attack

DDOS attack Outer Loop Target: Realmbot.mapped.livebin
Creates 400 sockets Creates 400 connections Sleeps 100 ms Inner Loop 2 Inner Loop 1 Outer Loop Inner Loop 3 Closes the sockets Comes around for another pass Target: Realmbot.mapped.livebin

Quiz Open up realmbot livebin and graph from the ws2_32 symbols…
What does the ioctl do? Hint: use google code search

Answer Makes it non-blocking, which means you don’t have to wait for connects, which makes all 400 sockets go out faster, in parallel

Command and Control Factors
Command Parsers Command and Control Factors

Starting Points Obvious Command Strings
String Comparison Routines, e.g. strcmp strchr Grow outward from networking loop

Soysauce static These status messages tell a lot about the malware’s capabilities. They are only a few hops from the sendto function.

Command Strings Commands are typically processed by a parser
There will be a string comparison There is a branching condition if the command matches There is a central location where the complete incoming command is stored This command buffer may be interrogated several times

Note the compare operation

Cmp bytes at these locations

Clean the graph so you only have the comparisons.
The graph is a long series of compares. soysauce This is the “current” command

soysauce From the top node, grow down ONE step. The new blocks are the handlers for each individual command.

Promote one of the commands to a layer of its own and drag-n-drop it to a new graph canvas
soysauce

Build a Diagram of a Specific Command Handler
soysauce Note, the command handler “goes back” to the command buffer numerous times. Could the command contain arguments that are being parsed?

This is a pointer to the data being written to the file
ECX must be a filename This is a pointer to the data being written to the file soysauce

The file is binary, not text.
It is being appended to, not created fresh from scratch. soysauce

The file pointer appears to point to a “scratchpad” buffer

Both the fwrite() call and the packet handler touch this scratchpad buffer

Buffer Sharing Follow buffers from the networking layer to find functions that implement command/control logic

Likely candidate. Used for the fwrite() data.
Review for pushes, we don’t see any. Packet handler is not using arguments. Must be shared buffer. The packet handler function would have pushes above if the function took arguments. Instead, we see the function accesses a global buffer – in other words, if coded in ‘c’, it would be a global variable like char gCommandBuffer[255] or something, and would not be passed around as an argument to the function. It’s hard coded. Likely candidate. Used for the fwrite() data.

A: entrypoint block into a network IO loop
In this slide we see an outer loop – the loop accesses a function to send and receive packets. A: entrypoint block into a network IO loop B: subroutine that sends/recv packets

Observations / Discoveries
Loops waiting for commands Commands are received over UDP Hard-coded IP address for packets (send/recv) Commands are stored in their own memory location short words There is a buffer area where binary data can be placed, like a scratchpad

Branch Logic CMP EAX, EBX CMP [EAX], EBX CMP EAX, 0x1000 TEST EAX, EAX

Branch Logic JNE jump if not equal JE jump if equal JA jump if above
JAE jump if above or equal JB jump if below JBE jump if below or equal JG jump if greater JGE jump if greater or equal JL jump if less JLE jump if less or equal

Branch Logic To implement a branch decision, the software will first perform a CMP and then follow it with a conditional jump. You can figure out the branch logic by putting the two together. <instruction address> : CMP EAX, 5 <instruction address> : JNE <target address> In the above, the program will branch to <target address> if EAX is not equal to 5.

TEST result of CALL The TEST instruction will often be used after a function call returns. Most compilers will put the return code for a function into the EAX register. So, you may see code like this: <instruction address> : CALL <target address> <instruction address> : TEST EAX, EAX <instruction address> : JE <target address>

Detecting size of data CMP DWORD PTR [<address>], 0
CMP WORD PTR [<address>], 0 CMP BYTE PTR [<address>], 0 Byte register: al, ah, bl, bh, cl, ch 16 bits: ax, bx, cx 32 bits: eax, ebx, ecx

Exercise Advanced Graphing Focus Type Interactive Analysis (MEP.EXE)
Description Use graphing techniques to quickly isolate Malware Analysis factors. Identify behavioral interrelationship between two of the factors. Time 25 minutes

Exercise Create a new project (Static PE Import)
Import MEP (Be careful, DON’T run it) Rough cut the strings Create layers for Communications Factors Command and Control Factors Build a graph that connects the Communications code with the Command and Control code Answer the questions in the back section of the handout (“Exercise 5 Questions”) BONUS: Graph the network traffic’s outer control loop

Review: Exercise What are some example strings used with the protocol? Identify the protocol(s) in use. Why is the channel between the COMs code and the Command and Control code important?

Bonus Answer: E-mail Parent Loop

Exercise Command and Control Factors Focus Type Interactive Analysis
Description Use graphing techniques to quickly isolate the Command and Control Factors associated with a captured piece of malware. Time 25 minutes

Exercise Create a new project (Static PE Import) Import soysauce2.dll
Name it “Soysauce 2” Import soysauce2.dll Answer the set of questions in the handout (“Exercise 10 Questions”)

Review: Exercise Is there a command buffer?
If so, where in memory is it located? Identify at least three commands that soysauce2 recognizes What do these commands cause soysauce2 to do? Hint: you may have to translate WS2_32 ordinals What protocol is used to receive commands?

Communications Factors
Crypto & Stego Communications Factors

Cryptography If the packet stream is encrypted, there will usually be a function or set of functions that decrypt the information In some cases, if the decryption is very simple, the decryption will be in-lined into the networking loop (no separate function) Look for XOR between bytes or between a byte and a hard-coded value

Stego Steganography is the art and science of writing hidden messages in such a way that no one apart from the sender and intended recipient even realizes there is a hidden message. By contrast, cryptography obscures the meaning of a message, but it does not conceal the fact that there is a message.

Random Number Generation
Another important factor of cryptography is the generation of random numbers. Most software does not do this very well, including malware. Look for “srand“ “srand” combined with a time function clock GetTickCount Etc.

Stego_example

Arithmetic Stego_example

Comparison Against a Value
Stego_example

Reading and Storing a Data-byte

Identifying READ and WRITE Operations

Linear Shift of Bytes

A B C D B C D E

Arithmetic against the byte that was read with getchar().
The and/not pair makes this seem like a mask. Data argument on stack, passed into function Finally, the last thing that gets done is the value derived from getchar() is COMBINED with a value that was an argument passed on the stack.

B C D E Data in register B C D Shift Right (SAR) B C D Data in register AND Mask C

Data from getchar() Data passed on stack AND mask NOT AND mask B C D W X Y Z C W W C OR’d together

The Steganography Routine
The routine is reading bytes The bytes are read into a shift register This means up to four bytes at a time are stored Many SHIFT and MASK operations AND, NOT operations There is a point where the byte is combined with a second, totally different byte This is the OR operation at the end Steganography is the art and science of writing hidden messages in such a way that no one apart from the sender and intended recipient even realizes there is a hidden message. By contrast, cryptography obscures the meaning of a message, but it does not conceal the fact that there is a message.

Unraveling Steganography
The routine is very complex to reverse engineer (a lot of arithmetic) We know Data read from somewhere is being COMBINED with a second set of data This combination uses heavy masking/shifting One set (probably the set being read with getchar) is being combined with a secret message. The final result is probably an encrypted byte, or a stego byte.

Reconstructing a crypto routine
DEMO Reconstructing a crypto routine encrypted_web_address.avi

Exercise Encryption Focus Type Interactive Analysis Description
Reverse engineer SearchIndex.EXE Time 25 minutes

Start Responder and create a new project (Physical memory) titled “searchindex.1”
Import the searchindex.vmem Extract searchindex.exe Show strings and filter for “crypto” Answer Question 1 Graph region around “crypto key set” Answer Question 2 Try to label subroutines and follow data locations Answer Questions 3-4 Pay close attention to the command line parameters Answer Questions 5-6 Try to build the entire communications backbone on the graph Try to find the functions which are responsible for encryption Answer Questions 7-8

Questions Does the program take command line parameters?
What function sets the crypto key? Is there a function for printing debug statements? Is there a default encryption key? What global flag controls whether crypto is to be used? Are there any other global flags for other command line parameters? Which function encrypts data and sends it over the network? Which function is responsible for decrypting incoming data?

These answers don’t match the example
Instructor Answers Does the program take command line parameters? Yes, -nocrypto, -debug What function sets the crypto key? Is there a function for printing debug statements? Yes Is there a default encryption key? Yes, "PiNkYsWoRlD" What global flag controls whether crypto is to be used? data_004082f8 Are there any other global flags for other command line parameters? Yes, -debug for example Which function encrypts data and sends it over the network? sub_00402AB0 Which function is responsible for decrypting incoming data? sub_

Exercise Recap Network packet crypto Crypto_around_flag.avi

Day 2, Part 3

Basic Computer Network Attack

Infecting Other Computers
Windows networking code Attack vectors

WNet API Enumerating other computers on the LAN Infecting drive shares
.INI files WNetOpenEnum Starts an enumeration of network resources WNetEnumResource Continues a network enumeration WNetAddConnection3 Makes a connection to a network resource WNetCancelConnection2 Terminates an existing network connection WNetGetConnection Retrieves the remote name of a network resource WNetGetUniversalName Maps a local path for a network resource WNetGetUser Retrieves user name used for network connection

Exercise CNA Factors Focus Type Interactive Analysis Description
Reverse engineer the USB media infection strategy Time 25 minutes

Start Responder and create a new project (Physical memory) titled “hellbot.1”
Import the hellbot.vmem Extract hellbot.exe, kernel32.dll, and ntdll.dll Show strings and filter for “.ini” and “.inf” Answer Question 1 Graph region around the filenames Look for the path or directory creation Look for file writing Answer Question 2 Use the code view to reverse the function code Answer Questions 3-5 Make a bookmark on this function

Questions What filenames stand out? What paths stand out? What register is used to store the lstrcat function pointer? What register is used to store the SetFileAttributes function pointer Where does the autorunme.exe file get copied from?

Instructor Answers What filenames stand out? Autorun.inf Desktop.ini What paths stand out? \ RECYCLER \ S What register is used to store the lstrcat function pointer? ESI What register is used to store the SetFileAttributes function pointer EBX Where does the autorunme.exe file get copied from? It’s a copy of the hellbot executable Bonus, the source path to the hellbot exe is obtained by using GetModulePath with a NULL module handle

Hellbot USB Key Infector
Exercise Recap Hellbot USB Key Infector Hellbot_autorun_recap.avi

Development Factors (Who Wrote It ?)

Who Wrote It? Characteristics of the Developer Code Quality Compiler
Compile Time / Time Zone Language Hints (Strings)

Programming Language Detecting Delphi (Pascal) Detecting VB
Detecting Compiler

Code Style / Quality Error Handling Functions Structured Coding
Exception Handlers Checking Return Values Functions Size Cohesion Coupling Structured Coding Switch{ } Statements / Multiple-IF constructs

Source Code Clues Embedded Paths Revision Control PDB file
Images / Resources Revision Control Tags indicating CVS usage

PDB Files Paths with .pdb files indicate the path where the source code was Can give many hints about the real name of a driver, even if it was renamed later Sometimes has project name, or even the user name of the creator

Control Classes Clues as to the libraries used
i.e., "msctls_statusbar32“ == MFC statusbar

Exercise Development Factors Focus Type Interactive Analysis
Description Use graphing techniques to quickly isolate the Development Factors associated with a VMware image. Time 25 minutes

Start Responder and create a new project (Physical memory project) titled “password.1”
Import the password1.vmem Extract b2new.exe and wmsdkna.exe Answer Questions 1-4

Questions What language was used to make these exe’s? Can you tell what version / compiler was used? Can you tell what the original project names are for these files? Are they using source code control? How can you tell?

What language was used to make these exe’s? Wmsdkns: Visual Basic
Instructor Answers What language was used to make these exe’s? Wmsdkns: Visual Basic Has “.vdp” file extension in string, Visual Basic Project File Has “__vba” in many function names, Visual Basic for Applications Can you tell what version / compiler was used? Wmsdkns: Visual Basic "C:\Program Files\Microsoft Visual Studio\VB98\VB6.OLB “C:\WINDOWS\system32\msvbvm60.dll\3” B2new: Visual C It includes functions from the msvcrt library B2new.exe: c or c++ The API calls, like sprintf, are used in c code Can you tell what the original project names are for these files? Wmsdkns: “runbll” (like rundll but trojan?) B2new: “loader_our” or “a_loader” Are they using source code control? How can you tell? Yes: "e:\projects\cvs_port\port\tools\loader_our\Bin\i386\a_loader.pdb"

Anti-debugging & Packing

Defensive Factors Overview
Firewall bypassing Anti-Virus Killing Rootkit/Stealth techniques Anti-Debugging Packing and Encrypting

Checking for Debugger IsDebuggerPresent Exception tricks
Register an exception handler, then see if any exceptions are intercepted If a debugger intercepts the exception, the malware detects it

Packing Results in limited symbol information
Many cross-references will not be available Requires data_CALL_PTR resolution

Packed Sections SECTION .Kaos12 SECTION ·Åµ´²»î¿

String and Path obfuscation

Packers & Function Loaders
Most malware will load a whole set of functions by name using GetProcAddress The functions appear by name as text No auto-labeling of the actual function pointers You can label them by hand

Function Loaders Function loaders usually load a whole set of functions at once You will see a series of ascii names and data_call_ptr’s used together, this is almost always a loading step

The graph shows the loading of a large set of named function pointers.
The code loads functions with GetProcAddress and LoadLibrary. The names of all the loaded DLLs and functions are clustered around this single node. MEP The graph shows the loading of a large set of named function pointers. This must be the function-loader part of the packer.

We can label each un-named data_call object with the proper name.
By examining the code, we see that each unlabeled address is associated with one of the named functions. MEP We can label each un-named data_call object with the proper name.

GetProcAddress Loading Function Pointers
Target: LanScanner

Resolving Call Pointers
DEMO Resolving Call Pointers Movie: resolving_data_call_ptrs.avi

Exercise Resolving Call Pointers Focus Type Interactive Analysis
Description Use graphing techniques to name data_call_PTR nodes with their proper function names Time 25 minutes

Start Responder and create a new project (Static Import) titled “data_calls.1”
Import the datacalls.1.mapped.livebin Drop the string “socket” onto the graph Grow up and find GetProcAddress Grow down to find data_CALL_PTR node associated with “socket” Use code view to determine how ASCII name and data_CALL_PTR node are related Answer Questions 1-2 Questions Which register is the function address returned in How many blocks are between “socket” and the data_CALL_PTR node it’s used with?

Use graph techniques to isolate the callers of socket
Promote the data_CALL_PTR to its own layer Hide the nodes that were using GetProcAddress Grow up Use graph techniques to label the functions and determine the callers socket recvfrom listen connect Answer Questions 1-4 Questions How many callers to socket? How many callers to recvfrom? How many callers to listen? How many callers to connect?

Instructor Questions & Answers
Which register is the function address returned in EAX How many blocks are between “socket” and the data_CALL_PTR node it’s used with? Two How many callers to socket? 8 How many callers to recvfrom? 1 How many callers to listen? 2 How many callers to connect? 4

Hooking and Stealth

Stealth Driver-assisted hiding
Use of thread or DLL injection so that new processes don’t need to be created Removal of the DLL from the list of loaded modules

Hooks Several common points where execution can be hooked
Many more non-obvious points Impossible problem to cover with 100% certainty In other words, the bad guys always have a way you didn’t think of yet

This is a diagram of all the places a rootkit can use in a hiding scheme. This slide requires a robust set of descriptive slides to go with it in order to be official “curriculum” so have Greg just talk to it in the class for now.

IDT Hooking Use of CLI and STI instructions around point of hook
Use of KeSetTargetProcessorDPC Queuing callbacks on each CPU core for multi-IDT table hooking KeQueryActiveProcessors

User-mode Hooking IAT hooks
Hooking code must run in or alter the address space of the target process If you try to patch a shared DLL such as KERNEL32.DLL or NTDLL.DLL, you will get a private copy of the DLL. Three documented ways to gain execution in the target address space CreateRemoteThread Globally hooking Windows messages Using the Registry HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Windows\AppInit_DLLs

IAT HOOK Import Address Table FunctionName or Ordinal 0x Table Entry

Some DLL IAT HOOK CODE FunctionName or Ordinal 0x CODE Table Entry

Some DLL IAT HOOK CODE Some Rootkit BAD CODE CODE

Modifying BaseRules.txt

Kernel-mode Hooking The operating system is global memory
Does not rely on process context Except when portions of a driver are pageable By altering a single piece of code or a single pointer to code, the rootkit subverts every process on the system

System Call KiSystemService Call Number 0x Table Entry System Service Descriptor Table USER MODE KERNEL MODE

System Call Kernel or module Call Number 0x Table Entry System Service Descriptor Table USER MODE KERNEL MODE

System Call Kernel or module Some rootkit System Service Descriptor Table USER MODE KERNEL MODE

System Call Kernel or module System Service Descriptor Table Some rootkit USER MODE KERNEL MODE

Memory Protection XP and later version of the operating system
Protect the System Call Table Protect the Interrupt Descriptor Table Protect code segments Writing to “read and execute only” memory causes BSoD

The CR0 Modify Memory Here… // UNProtect memory __asm { push eax
mov eax, CR0 and eax, 0FFFEFFFFh mov CR0, eax pop eax } Modify Memory Here… // REProtect memory __asm { push eax mov eax, CR0 or eax, NOT 0FFFEFFFFh mov CR0, eax pop eax }

BaseRule CodeBytes:1.0:1:50 0F 20 C0 25 FF FF FE FF 0F 22 C0 58:ALL:These code bytes disable memory protections, this is highly suspicious // UNProtect memory __asm { push eax mov eax, CR0 and eax, 0FFFEFFFFh mov CR0, eax pop eax }

DEMO System Call Hooks SSDT_HOOK_RESOLUTION.avi

NOTES ON DEMO Import virus.vmem and follow the three SSDT hooks that hide_evr puts in place

Exercise Firewall Killer Focus Type Interactive Analysis Description
Reverse engineer the firewall defense Time 25 minutes

Start Responder and create a new project (Static Import) titled “firewall.1”
Import the firewall_killer.vmem Extract 2e45.exe Find out how the malware protects against firewalls and anti-virus Answer Question 1 Find the function that is called multiple times in a row with firewall or antivirus program names Reverse engineer that function Answer Questions 2-3

Questions Does the program attempt to stop more than one tool or program? Which registry key does the program make values under? What is the name of the program which is set to debug the firewalls?

Answers Does the program attempt to stop more than one tool or program? Yes, there is a long list of programs Which registry key does the program make values under? Image File Execution Options What is the name of the program which is set to debug the firewalls? ALG.EXE

Exercise Recap Firewall Killer Firewall_killer_1.avi

Greg Hoglund Martin Pillion

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