CSC 482582 Computer Security Incident Response CSC 482582

CSC 482/582: Computer Security Incident Response CSC 482/582: Computer Security

Incident Response 1. What is an Incident? 2. Phases of Incident Response 1. 2. 3. 4. 5. 6. 7. 8. Preparation Identification Containment Damage Assessment Preserve Evidence Eradication Recovery Follow-up CSC 482/582: Computer Security

What is an Incident? Violation of security policy �Unauthorized access of information �Unauthorized access to machines �Embezzlement �Virus or worm attack �Denial of service attacks �Email spam or harassment CSC 482/582: Computer Security

Detecting an Incident �Catching perpetrator in the act �Unauthorized logins, NIDS alerts �Noticing unauthorized changes in the system �Receiving a message from another site, saying that your site was used to launch an attack on them �Strange activities on system �crashes, random reboots, slow performance CSC 482/582: Computer Security

Incident Response �Restoring system to satisfy site security policy �Phases: 1. 2. 3. 4. 5. 6. 7. 8. Preparation for attack (before attack detected) Identification of attack Containment of attack (confinement) Damage assessment Preserve evidence (if necessary) Eradication of attack (stop attack) Recovery from attack (restore system to secure state) Follow-up to attack (analysis and other actions) CSC 482/582: Computer Security

Preparation �Configure intrusion detection systems �Determine your response goals �Document incident response procedures �Who to contact? �What to do? �Organizing a CSIRT �Finding and training personnel �Hardware/software necessary for investigation CSC 482/582: Computer Security

Incident Response Goals 1. 2. 3. 4. 5. 6. Determine whether a security breach occurred Contain the intrusion to prevent further damage Recover systems and data Prevent future intrusions of same kind Investigate and/or prosecute intrusion Prevent public knowledge of incident CSC 482/582: Computer Security

Identification �Who/what reported incident �Date and time of the incident �Nature of the intrusion �What level of unauthorized access was attained? �Is it known to the public? �Hardware/software involved �How critical are the affected systems? �Assemble CSIRT �Team membership may vary based on nature of incident CSC 482/582: Computer Security

Containment �Limit access of attacker to system resources �Containment method depends on criticality of systems and extent of intrusion �Monitoring intruder �Reducing intruder’s access �Deception �De-activating the affected account � Need to kill active processes too �Blocking access to system via firewall �Pulling network/phone cable �Powering down system CSC 482/582: Computer Security

Monitoring �Records attacker’s actions; does not interfere with attack �Idea is to find out what the attacker is after and/or methods the attacker is using �Problem: attacked system is vulnerable throughout �Attacker can also attack other systems �Example: type of operating system can be derived from settings of TCP and IP packets of incoming connections �Analyst draws conclusions about source of attack CSC 482/582: Computer Security

Reducing Access �Reduce protection domain of attacker �Problem: if defenders do not know what attacker is after, reduced protection domain may contain what the attacker is after �Stoll created document that attacker downloaded �Download took several hours, during which the phone call was traced to Germany CSC 482/582: Computer Security

Deception Honeypot: system designed for intruders to attack, to waste their time and to allow safe monitoring �ex: The Honeynet Project, honeyd Deception Tool Kit �Creates false network interface �Can present any network configuration to attackers �When probed, can return wide range of vulnerabilities �Attacker wastes time attacking non-existent systems while analyst collects and analyzes attacks to determine goals and abilities of attacker Experiments show deception is effective response to keep attackers from targeting real systems CSC 482/582: Computer Security

Honeynet Project Tool development �Environment simulation: virtual machines �Data control: firewalling tools to limit attacker activities to avoid damaging other systems �Data collection: network and keystroke loggers �Data analysis: tools to extract relevant data from tcpdump logs and more Research and documentation �Analysis of attacker and honeypot techniques �Analysis of particular attacks CSC 482/582: Computer Security

Damage Assessment: Data �System date and time when assessment began �List of users currently logged in �Time/date stamps for filesystem �List of processes �List of open network sockets �Associated applications �Associated systems �System configuration files �Log and accounting files �System date and time when assessment complete CSC 482/582: Computer Security

Data Assessment: Procedure Use trusted binaries from floppy/CDROM �Use a trusted shell �Set PATH to only use floppy/CDROM tools System date and time: > date Mon Apr 26 13: 33: 08 EDT 2004 List of current users > w 1: 33 pm up 30 day(s), 3: 34, 3 users, load avg: 0. 26 User tty login@ idle JCPU PCPU what root console 9: 21 am 4: 13 -sh wald pts/14 15 Apr 04 3: 25 66: 24 63: 06 -bash root pts/20 9: 21 am 4: 12 -sh novi pts/6 Sat 4 pm 17 52 -bash CSC 482/582: Computer Security

Data Assessment: Procedure File date/time stamps ls –al. Ru / >/mnt/floppy/atime ls –al. Rc / >/mnt/floppy/ctime ls –al. R / >/mnt/floppy/mtime Network ports > netstat –anp Active Internet connections (servers and established) Proto Local Addr Foreign Addr State Program tcp : : : 22 : : : * LISTEN 26327/sshd tcp 10. 17. 0. 110: 22 10. 1. 0. 90: 51327 ESTABLISHED 28644/sshd: tcp 127. 0. 0. 1: 25 0. 0: * LISTEN 1840/sendmail udp 0. 0: 32768 0. 0: * 1456/rpc. statd udp 0. 0: 68 0. 0: * 1363/dhclient udp 0. 0: 111 0. 0: * 1436/portmap CSC 482/582: Computer Security

Data Assessment: Procedure Running Processes > ps aux USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND root 1 0. 0 1928 520 ? S Apr 17 0: 04 init [5] root 1403 0. 0 2128 580 ? S Apr 17 0: 01 syslogd -m 0 rpc 1436 0. 0 2516 576 ? S Apr 17 0: 00 portmap rpcuser 1456 0. 0 2916 832 ? S Apr 17 0: 00 rpc. statd smmsp 1849 0. 0 0. 2 7324 2520 ? S Apr 17 0: 00 sendmail: Queue runner@01: 00 for /var/spool/clientmqueue root 1970 0. 0 2992 348 tty 3 S Apr 17 0: 00 /sbin/mingetty 3 root 26327 0. 0 0. 1 4728 1504 ? S Apr 21 0: 00 /usr/sbin/sshd waldenj 28646 0. 0 0. 2 8548 2560 ? S 11: 12 0: 00 sshd: waldenj@pts /7 waldenj 28647 0. 0 0. 1 6800 1500 pts/7 S 11: 12 0: 00 -bash root 28767 0. 0 0. 1 6572 1356 pts/7 S 13: 44 0: 00 bash root 28789 0. 0 3624 876 pts/7 R 13: 49 0: 00 ps aux CSC 482/582: Computer Security

Data Assessment: Procedure Collect system configuration �Check for sniffers: ifconfig �/etc/passwd, /etc/shadow, /etc/group �Scheduled jobs: cron and at �System init files: /etc/inittab, /etc/rc. d Collect system log files �Login logs in /etc/utmp, /etc/wtmp �Check /etc/syslog. conf �Log files in /var/adm, /var/log �Process accounting files in /var/acct �Shell history files, e. g. , ~/. bash_history CSC 482/582: Computer Security

Preserve Evidence �In-depth live system investigation �Construct a bit-level copy of entire hard disk or partition forensic examination �Create image in single-user mode md 5 sum /dev/hda dd if=/dev/hda conv=noerror, sync | ssh desthost “cat >disk. img” desthost> md 5 sum disk. img CSC 482/582: Computer Security

Eradication Do nothing Kill attacker’s processes and/or accounts Block attacker’s network access to system Patch and repair what you think was changed, then resume operation 5. Investigate until root cause discovered, then restore system from backups and patch security holes 6. Call law enforcement before proceeding further 1. 2. 3. 4. CSC 482/582: Computer Security

Follow-Up �File reports with law enforcement, vendor, or regulatory agency �File insurance claims if relevant �Notify administrators of other affected systems �Disciplinary actions against employees for internal attacks �Update security of computer networks/systems �Review handling of the incident �Update incident handling policy/training CSC 482/582: Computer Security

Counterattacking Use legal procedures �Collect chain of evidence so legal authorities can establish attack was real �Check with lawyers for this � Rules of evidence very specific and detailed � If you don’t follow them, expect case to be dropped Technical attack �Goal is to damage attacker seriously enough to stop current attack and deter future attacks CSC 482/582: Computer Security

Consequences 1. Counterattack may harm innocent party • Attacker may have broken into source of attack or may be impersonating innocent party 2. Counterattack may have side effects • If counterattack is flooding, may block legitimate use of network 3. Counterattack antithetical to shared use of network • Counterattack absorbs network resources and makes threats more immediate 4. Counterattack may be legally actionable CSC 482/582: Computer Security

Example: Counterworm �Counterworm given signature of worm �Counterworm spreads rapidly, deleting all occurrences of original worm �example: Welchia/Nachi hunts Blaster/My. Doom worms �Issues �How can counterworm be set up to delete only targeted worm? �What if infected system is gathering worms for research? �How do originators of counterworm know it will not cause problems for any system? � And are they legally liable if it does? CSC 482/582: Computer Security

Key Points 1. 2. 3. 4. 5. 6. 7. 8. Security incidents come in many forms Prepare for an incident before one occurs Understand your response goals Don’t trust the affected system in any way Know your available data sources and their uses Save data offline for later analysis Legal issues of counterattacks Phases of Incident Response: Preparation, Identification, Containment Damage Assessment, Preserve Evidence Eradication, Recovery, Follow-up CSC 482/582: Computer Security

References 1. 2. 3. 4. 5. 6. Brownlee, N. and Guttman, E. , “RFC 2350 - Expectations for Computer Security Incident Response, ” http: //www. faqs. org/rfcs/rfc 2350. html, 1998 CERT, “Computer Security Incident Response Team (CSIRT) FAQ, ” http: //www. cert. org/csirts/csirt_faq. html Cheswick, William, Bellovin, Steven, and Rubin, Aviel, Firewalls and Internet Security, 2 nd edition, Addison-Wesley, 2003 Fraser (ed. ), “RFC 2196 - Site Security Handbook, ” http: //www. faqs. org/rfcs/rfc 2196. html, 1997 Garfinkel, Simson, Spafford, Gene, and Schartz, Alan, Practical UNIX and Internet Security, 3 rd edition, O’Reilly & Associates, 2003 Mandia, Kevin, Prosise, Chris, and Pepe, Matt, Incident Response & Computer Forensics, 2 nd edition, Mc. Graw-Hill, 2003 CSC 482/582: Computer Security