HijackThis - A general Homepage Hijacker Detector and Removal Tool By: Tahira Farid Project 1 Fall 2004

Overview Browser Hijacking and Why The Techniques Preventing a Hijack HijackThis- A Hijack Removal Tool Download Information Getting around with the tool

Overview (cont.) Testing Summary Important things learnt Useful Links References

What is Browser Hijacking? Where browser’s default settings is forcibly modified by using scripting tools Spyware takes over our internet settings, Redirects our searches and steals our homepage adding links to favourites changing homepage persistently - scripting - changing registry values - auto-running programs - secret files put on the hard disk

Why Hijacking? Bring us back to a website or a sponsor’s site of Hijacker’s choice Generate advertising revenues Keep users trapped in their sites Expand website’s traffic Is it Reversible? - as easy as to switch the internet options back -as crucial as to undo the changes by going to windows registry

The Techniques Multiple Windows pop-ups while leaving the site Windows half off screen hard to close and allows no control Offering “freebies” in their sites Installing AOL software, messenger, ICQ adds to IE’s trusted sites zone without our permission-can download activeX, run scripts, perform various actions. Removing internet options from tool menu and control panel Changing reg settings to reset homepage Installing program to reset homepage on reboot

Preventing Hijack Various anti-hijacking and anti-virus tools available. HijackThis- utility tool to remove browser hijacks, viruses, trojans & spyware Does not target specific prog./URLs Targets methods used by hijackers

HijackThis Developed by Marijn Freeware 178 KB latest version: Intended for advanced users Increasingly updated to detect & remove new hijacks Runs on all windows OS

Download Info & caution Required to place it in its own folder otherwise backups will not be made. Recommended to be used after running spybot or spyware/hijacker remover- malware files will be left behind. Requires knowledge in windows and OS in general. If deleted entries without knowing- problems as IE not working, running windows.

Caution(cont) Scans registry and various files in HD. Entries similar to what a spyware/hijacker program would leave behind Interpreting the results can be tricky. Legitimate programs get installed in similar way hijackers get installed. Extra causion should be taken fixing a problem.

Getting started Go to the desired folder where hijackthis was created from zip unpack. Double click on hijackthis.exe

Scan results Each line starts with a section name

Info on selected items To know info about a selected obj

Fix entries Select an item to fix/remove

Restoring items deleted mistakenly We can make backup & restore items for erroneous scenarios for items which were removed but legitimate. Under config button

Generating startup listing Has a built-in tool to generate listing of all the prog that launch when comp starts. Under config, Misc tools option.

Process Manager Built-in tool to 1)Kill processes that are currently running 2)Check what DLLs are loaded in a particular process Under config, Misc tools option

Process Manager (cont.)

Hosts File Manager View our host file, Delete lines Toggle lines on/off HijackThis will add a “#” sign before the line to comment it out so that it will not be used by Windows.

Delete on reboot Sometimes files obstinately reject to get deleted from the system by any traditions means. Could be virus/ spyware HijackThis allows windows to delete the file on reboot.

HijackThis log Each line on the scan list starts with a section name Each entry has a 2-letter code to say what it is.

Testing Windows XP SP2 Running spybot S&D, ad-aware Specific problem in IE: always redirects to Even using spybot S&D, AboutBuster, Spywareblaster, Ad-aware problem was still there Following entries were deleted after scan: O2 - BHO: (no name) - {549B5CA7-4A86-11D7-A4DF BB3} - (no file) 02 entries refers to BHO- plugins for browser that extend the functionality of it. Used by spyware & legitimate programs. CLSID refers to reg. entries that contains info about BHO/toolbars. This particular entry means the entry exists in the registry but the associated file does not exist. Therefore cleaned to tidy up the registry.

Testing (cont.) R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Local Page = R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Local Page = R0,R1 entries refer to IE start page & search functions. The url R0, R1 are pointing to is unwanted. Therefore cleaned to get rid of it.

Testing (cont.) O4 - HKLM\..\Run: [SysTime]  startup item C:\WINDOWS\system32\systime.exe  Trojan downloaded O4 - HKCU\..\Run: [SysTime] C:\WINDOWS\system32\systime.exe 04 entries refer to app that are listed in certain keys in reg/startup folders and are loaded automatically when windows starts. Here 04 entry shows a CoolWebSearch Trojan. Therefore fixed by HijackThis. The corresponding file C:\WINDOWS\system32\systime.exe was deleted by running windows on safe mode after fixing with HijackThis.

Testing (cont.) O16 - DPF: {15AD4789-CDB4-47E1-A9DA-992EE8E6BAD6} entries refer to ActiveX obj-programs that are downloaded from websites and stored in our computer. Also referenced in the reg by their CLSID. Here the object/URL could not be recognized from where it was downloaded. Therefore cleaned by HijackThis. HijackThis also deletes the offending file from C:\Windows\Downloaded Program Files- where the these types of objects are stored.

Testing (cont.) Booting with safe mode following file was deleted C:\WINDOWS\system32\systime.exe Temp internet files were deleted System rebooted normally, Ad-aware was run to do some more cleanup. No bad entries were found in the new log.

Summary HijackThis is a very powerful tool to root out serious infestation or attack in our system. we should be cautious enough, since incorrectly removing inappropriate objects can cause problems with legitimate programs and compromise our system. Many online forums & tutorials for inspecting logfiles. Useful links available for CLSID, startup lists. we need a great deal of devotion, commitment and knowledge towards our system security. HijackThis by itself can not make our system secure from Hijackers, we need other relevant tools as well to detect and remove spyware and viruses.

Important things learnt In order to keep computer clean and secure: Make our Internet Explorer more secure by customizing security options. Use an AntiVirus Software Use Spyware & Malware remover utility tools Spybot S&D, Ad-aware, CWShredder, HijackThis, SpywareBluster Update our AntiVirus Software Use a Firewall Visit Microsoft's Windows Update Site Frequently Update all these programs regularly

Useful links HijackThis log file analysis: TonyK's Browser Helper Obj (BHO) & Toolbar list: PacMan's Start-up list to find the entry and see if it's good or bad.

References html html ?showtutorial=42#RDiag ?showtutorial=42#RDiag

Thank You!