Looking at Vulnerabilities Dave Dittrich University of Washington cac.washington.edu

Overview Background attack concepts Your typical look at Vulnerabilities, Risk vs. Cost A (real!) complex attack scenario A different view of vulnerabilities Trust relationships Attack trees Atypical/uncommon vulnerabilities

Stepping Stones

Internet Relay Chat (IRC)

IRC w/Bots&BNCs

Distributed Denial of Service (DDoS) Networks

Typical DDoS attack

DDoS Attack Traffic (1) One Day Traffic Graph

DDoS Attack Traffic (2) One Week Traffic Graph

DDoS Attack Traffic (3) One Year Traffic Graph

SANS Top 20 Vulnerabilities Windows Top Internet Information Server (IIS) 2. Microsoft Data Access Server (MDAC) 3. SQL Server 4. NETBIOS 5. Anonymous login/null session 6. LAN Manager Authentication (Weak LM hash) 7. General Windows Authentication (Accounts w/o pwd, bad pwd) 8. Internet Explorer 9. Remote Registry Access 10. Windows Scripting Host Unix Top Remote Procedure Call (RPC) services 2. Apache Web Server 3. Secure Shell (SSH) 4. Simple Network Management Protocol (SNMP) 5. File Transfer Protocol (FTP) 6. Berkeley “r” utilities (trust relationships) 7. Line Printer Daemon (LPD) 8. Sendmail 9. BIND/DNS 10. General Unix Authentication (accounts w/o pwd, bad pwd)

High Low password guessing password cracking exploiting known vulnerabilities disabling audits back doors hijacking sessions sniffers packet spoofing GUI automated probes/scans denial of service www attacks Tools Attackers Intruder Knowledge Attack Sophistication “stealth” / advanced scanning techniques burglaries network mgmt. diagnostics distributed attack tools binary encryption Source: CERT/CC (used w/o permission & modified “Can you say ‘fair use?’ Sure, I knew you could.” IHO Fred Rogers ) Attack sophistication vs. Intruder Technical Knowledge

Cost vs. Risk 101

Another view of Cost vs. Risk

UW Medical Center “Kane” Incident Goal: How hard to obtain patient records? Windows 98 desktop w/trojan or no pwd Sniffer Linux server -> Windows NT PDC/F&P server Unix server Windows PDCs, BDCs Windows Terminal Server (>400 users) Access database file (>4000 patient records: Name, SSN, Home number, treatment, date… ) SecurityFocus -> ABC News

Trust relationships Client Server IP based ACLs Shared password/symmetric key Shared network infrastructure Sensitive data in Sensitive files on servers

Attack Trees “Secrets and Lies,” Bruce Schneier, ISBN , chapter 21 Goal is root node: Sub-goals are lower nodes/leaves And/Or relationship between nodes Attributes: Likelihood, equipment required, cost of attack, skill required, legality, etc.

Attack Tree Example 1

Attack Tree Example 2

Attack Tree Example 3 Survivability Compromise: Monitor network traffic OR: 1. Install sniffer on desktop. OR: 1. Use trojan horse. 2. Use remote exploit. 3. Use Windows remote login service. OR: 1. Use passwordless Administrator account. 2. Brute force passwords on all listed accounts. 3. Brute force passwords on common accounts. 2. Install sniffer on Unix/Windows server OR: 1. Use remote exploit. 2. Steal/sniff password to root/Administrator account. 3. Guess password to root/Administrator account. 3. Man-in-the-middle attack on SSL/SSH. …

Attack Tree Example 4 (Nested) Survivability Compromise: Disclosure of Patient Records OR: 1. Attack Med Center network using connections to the Internet OR: 1. Compromise central patient records database (PRDB). AND: 1. Identify central PRDB. OR: 1. Scan to identify PRDB. 2. Monitor network traffic to identify PRDB. 2. Compromise central PRDB. OR: 1. Use Remote Exploit. 2. Monitor network traffic to sniff pwd to account. 3. Guess password to account. 2. Obtain file(s) containing patient records. OR: 1. Monitor network traffic to capture patient records. 2. Compromise file server or terminal server. OR: 1. Use Remote Exploit. 2. Monitor network traffic to sniff Administrator pwd. 3. Guess password to User/Administrator account.

Atypical Vulnerabilities Network Infrastructure Special Devices Non-technical (Social) Issues

Border Routers BGP (route insertion/withdrawal) Address forgery Source routing Denial of Service Remote service exploit & “Root kits” Lack of visibility/access to traffic flows

Internal Routers/Switches OSPF, RIP & other protocols Address forgery ARP spoofing Sniffing (SNMP community string, pwd) Denial of Service Lack of visibility/access to traffic flows

Servers Gateways to legacy apps Web apps Insufficient logging/auditing Hiding in plain sight Control of software configuration

Network Printers Change “Ready” message FTP bounce scan, other scanning File cache SNMP/web admin front ends, back doors Disclosure of print jobs Passive monitoring Redirection of print jobs

Medical “devices”, photocopiers, printers Proprietary or OEM OS (e.g., Solaris, IRIX) Many (non-essential) services turned on Typically behind the curve on patches Remote management (HTTP, SNMP) Heavy use of unencrypted protocols (e.g., FTP, LPR, Berkeley “r” utilities) “What? The hackers are back?”

PBXs, voice services Monitoring Theft of Service Fraud/social engineering Denial of Service Malware Cache (PC based VM)

Social Issues Not recognizing threats Assuming attacks are simple Assuming things are what they seem (e.g., Slammer, Nimda) Assuming attacks/defenses are direct Assuming you have it handled

Summary Vulnerabilities exist in places you might not think Vulnerabilities are additive, interrelated Complex attacks call for complex defenses/response If you’re not learning something new every day, you’re falling behind your adversary Questions?

References UW Medical Center Attack trees Networking

References (cont) Routers us-02-akin-cisco.ppt us-02-akin-cisco.ppt BGP, OSPF df df

References (cont) Switches, ARP, local network attacks Mike-Beekey.ppt Mike-Beekey.ppt Printers PBXs DDoS, “root kits”