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Bots and Botnets The Automation of Computer Network Attacks

Bots and Botnets The Automation of Computer Network Attacks. Written and researched by David Dittrich The Information School University of Washington. Presented by Amelia Phillips. Overview. Where did “bots” come from? How do they work? How botnets are built How are they used for attacking?

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Bots and Botnets The Automation of Computer Network Attacks

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  1. Bots and BotnetsThe Automation of Computer Network Attacks Written and researched by David DittrichThe Information SchoolUniversity of Washington Presented by Amelia Phillips

  2. Overview • Where did “bots” come from? • How do they work? • How botnets are built • How are they used for attacking? • How do you defend against them? • Botnets in action!

  3. Where did “bots” come from?

  4. Internet Relay Chat http://www.newircusers.com/network.html

  5. IRC Commands http://www.newircusers.com/ircmds.html

  6. DCC Commands http://www.newircusers.com/ircmds.html

  7. mirc IRC client http://www.irchelp.org/irchelp/ircii/ircii.gif

  8. IRC bots http://www.irchelp.org/irchelp/misc/botfaq.html#1

  9. Typical uses • Keep track of channel users • Transfer files automatically • Enforce kick/ban lists of “bad” users • Protect channels from takeover

  10. How do bots work?

  11. “Net split” attack (before) Owner

  12. “Net split” attack (after) DDoSAttack Owner Attacker

  13. “Net split” attack (defense) Owner Bot Bot Bot Bot

  14. Eggdrop config file

  15. Eggdrop config file

  16. Translated eggdrop config

  17. Encrypted communications

  18. My how these bots have grown…

  19. Increasing Attack Sophistication Attack sophistication vsIntruder Technical Knowledge binary encryption Tools “stealth” / advanced scanning techniques High denial of service packet spoofing distributed attack tools sniffers Intruder Knowledge www attacks automated probes/scans GUI back doors network mgmt. diagnostics disabling audits hijacking sessions burglaries Attack Sophistication exploiting known vulnerabilities password cracking Attackers password guessing Low 1980 1985 1990 1995 1998 2001 Source: CERT/CC

  20. Bot features then (1994) • Channel controls • Simple file transfers • Password protected back door

  21. Growth of botnets

  22. Growth of botnets

  23. Bot features now (2004) http://www.lurhq.com/phatbot.html

  24. Bot features now (2004) http://www.lurhq.com/phatbot.html

  25. Advances in C2 & security features • Encryption of communications • Use of Peer-to-Peer • “Swiss Army knife” feature set • Polymorphism and Anti-Anti-Virus • Anti-forensics/Anti-debugging

  26. Waste network http://waste.sourceforge.net/index.php?id=information

  27. Combining Waste networks http://waste.sourceforge.net/docs/docs.html

  28. Relationship to DDoS (Dates approximated) DDoS Botnets Leads to Classic DDoS(Handler/Agent) Single threaded DoS Bots 2000 2005 1997 1998 1999 2001 2002 2003 2004 1996

  29. How are botnets built?

  30. “It takes malware…”

  31. Strategies in botnet creation • Learn about IRC commands and features • Choose a bot or “blended threat” kit • Get access to some computers • Trade for CCs, other hosts/accounts, or buy • Use a virus, trojan horse, or other “sploit” • “War drive” to find free wireless access • Herd your bots • Try to keep someone from finding/stealing them

  32. Botnet used for recruitment

  33. Bot propagation “Trends in Denial of Service Attack Technology,” http://www.cert.org/archive/pdf/DoS_trends.pdf

  34. Malicious use of botsand how to respond

  35. The new spammers

  36. Phases of botnet/DDoS attacks • Phase one: “own” a [bleep!]load of computers! • Phase two: use them to attack others • DDoS • More “owning” • Anonymity while doing crimes

  37. The new gangsters

  38. Phatbot DDoS attack methods • Two types of SYN floods, UDP & ICMP • “Targa” (random IP protocol, fragmentation, and frag offset) • “Wonk” (one SYN packet followed by 1023 ACK packets) • HTTP (single GET w/delay in hours, or recursive GET) • Many attacks support various spoofing (/16, /24 or all 32 bits)

  39. Botnet used for DDoS attack

  40. Assoc. of Remote Gambling Operators • $73M lost to extortion in 2004 • $10k - $40k per attack (some multiple) • Each attack lasts hours to > 1 week • 518,000 “computers” used in one attack • 3 arrested in July 2004 • By following the $$, not by traceback • Several gangs still active worldwide “Gambling Sites, This Is A Holdup: Organized criminal hackers threaten to paralyze their networks if they don't pay up,” Business Week, http://www.businessweek.com/magazine/content/04_32/b3895106_mz063.htm

  41. Strategies in botnet defense • Learn about IRC commands and features • Learn about bots, DDoS, other malware(http://staff.washington.edu/dittrich/misc/ddos, and book…) • Gain data collection and analysis skills • Host forensics • Network forensics • Reverse engineering, programming, scanning, etc. • Analyze traffic flows, patterns • Key goals: Identify structure and C2 methods

  42. Weaknesses in botnets Recruitment/Herding Scanning/ Attacking Command/ Control

  43. Botnets in action

  44. Report of activity

  45. Nmap scan

  46. Services provided by bot

  47. Feedback to attacker! “My” IP address!

  48. Other compromised hosts

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