Fast Detection of New Malicious Domains using DNS
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OpenDNS Security Researcher Dhia Mahjoub presented this talk at BSides Raleigh on October 18th, 2013.
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Fast Detection of New Malicious Domains using DNS
- 1. Fast Detection of New Malicious Domains using DNS Dhia Mahjoub OpenDNS October 18th, 2013
- 2. Outline • • • • • • • • DNS infrastructure Monitoring/detec@on system Domain/IP watch list Post-‐detec@on filtering Implementa@on Use cases FF Kelihos domains, EK domains, Ransomware, Trojans Conclusion
- 3. DNS big data querylogs authlogs
- 5. Malicious use of DNS • Botnet/Malware C&C • DGAs • Fast flux • DNS amplifica@on aXacks
- 6. Our Focus • AXack domains, not compromised domains -‐>Exploit kit domains -‐>Malware delivery domains
- 7. Fast Flux Monitoring/Detec@on System • TTL=0 Kelihos Fast Flux domains 7-‐months study presented at APWG eCrime 2013 hXp://labs.umbrella.com/2013/09/24/real-‐@me-‐monitoring-‐kelihos-‐fast-‐ flux-‐botnet-‐case-‐study-‐presented-‐apwg-‐ecrime-‐2013/ • TTL=150 • TTL=300 • TTL=1440, spam domains
- 8. Fast Flux Monitoring/Detec@on System While true 1. Select a seed of Kelihos domains w/ a confirmed profile 2. Con@nuously milk domains for IPs 3. Con@nuously “inverse lookup” IPs in passive DNS, for new domains that start resolving to these IPs 4. Check detected domains for known profile (e.g. TTL, registra@on, existence of payload, etc) 5. Add new domains to the ini@al seed
- 9. Kelihos domains profile • Various gTLDs, ccTLDs, 1 single IP, TTL=0, hosted on Kelihos botnet IP pool (growing), infected individual machines, recent registra@on, delivering malware executables with known names • Recorded case(s) of domain resolving to several IPs with TTL=600, cocala.asia, or TTL=300
- 10. Generalized Monitoring/Detec@on System • While true • Read IP watch list, launch parallel process for every IP • A process performs IP inverse lookup against DNSDB • Every process returns new domains for IP • Join all processes’ output, check against blacklist • Keep only new domains • Perform parallelized post discovery checks using different heuris@cs: traffic paXern, name paXern, extra IP reputa@on check, etc. • Add new domains to blacklist
- 11. Watch list selec@on • Con@nuous background process • Different methods/heuris@cs to harvest new IPs with high risk poten@al • Use fresh blacklist, 3rd party BL domain list
- 12. Watch list selec@on (cont’d) • Resolve IPs and cluster by popularity, age, aXack theme -‐>IP observed to host exclusively EK domains or ransomware -‐>Similar name paXern of hosted domains -‐>Similar traffic paXern • Remove IPs on large shared hos@ng providers unless excep@ons (e.g keep OVH CIDR dedicated to malware), sinkholes, other IP profiles that could cause FPs
- 13. Harves@ng bad IPs • When we discover new high risk IPs, why not just block IPs? Sure, we can, and we open do! • But you lose intel and inves@ga@ve material related to domains: name paXerns, DGAs, dynamic DNS usage, malicious subdomains under legi@mate compromised domains
- 14. Post detec@on checks • Traffic paXern, name paXern, further IP reputa@on check • If a spike or beginning of spike, then poten@al risk domain • Exclude spam domains • But spike means domain has already delivered aXack
- 15. Post detec@on checks (cont’d) • So preemp@ve blocking is necessary if domain has high poten@al of being an aXack domain • Not everything should be automated • Human intel and inves@ga@on needed at @mes to remove FPs and add FN back -‐> Fine-‐tune the model
- 16. Plarorm and tools used -‐Pig on Hadoop cluster -‐Raw logs on HDFS -‐Indexed DNSDB in HBase -‐Python, shell, Gnu Parallel
- 17. System in a nutshell -‐>Constantly running process of harves@ng fresh high risk IPs -‐>Constantly running process of discovering fresh malicious domains -‐>Constantly querying DNSDB with IP inverse lookups Backend: -‐>DNSDB constantly fed with authorita@ve traffic from all resolvers
- 18. Whitelist • IPs hos@ng spam domains A lot of IPs on AS15149, e.g. 216.169.100.133 • Shared hos@ng IPs with a large number of general purpose websites
- 19. Use cases • • • • • • • Kelihos fast flux botnet Fake AV .pl domains used for Kovter and other Godaddy compromised domains Cryptolocker CnC discovery NuclearPack EK Browlock domains
- 20. Kelihos Fast flux • • Kelihos fast flux botnet Up un@l Sep 16th, about 984 domains (and subdomains) hosted on 28757 IPs hXp://labs.umbrella.com/2013/09/24/real-‐@me-‐monitoring-‐kelihos-‐fast-‐ flux-‐botnet-‐case-‐study-‐presented-‐apwg-‐ecrime-‐2013/ • • Sample of domains of Aug-‐Sep 399 domains on 8159 IPs
- 22. Fake AV • 82.208.40.11 hos@ng 23502 Fake AV, Fake SW domains for 76 days hXps://www.virustotal.com/en/ip-‐address/82.208.40.11/informa@on/ • • Free domains under cz.cc, uni.me 176.31.125.91 hos@ng 6687 similar domains for 66 days
- 23. .pl used for ransomware Sample of .pl domains 19267 domains on 12 IPs 3 level domains f9photo.ucuphahnui.kepno.pl 95oishi.maimuofief.pisz.pl • First 2 labels are DGAs • • • from malware.dontneedcoffee.com • Used in malver@sing campaigns on adult websites leading to Exploit kit domains and Kovter ransomware dropping hXp://www.malekal.com/2013/07/31/en-‐urausy-‐adulrriendzfinder-‐ malver@sing-‐banner/
- 25. NuclearPack EK -‐>1523 domains on 198.50.225.113 • 2 level domains under .biz • 1st label is random, 16 2LDs registered July 28th • hxxp://dreut.valen@nespell.biz: 59902/0e724s2d10467436c6149sce02712a.html -‐>1378 domains on 198.50.235.198 • 2 level domains under .biz • 1st label is random • hxxp://u5s1av.diwalipearl.biz: 55252/5a9b00e34d8b18cb571ba56a357cfafc.html
- 26. NuclearPack EK -‐>198.50.235.200 became ac@ve on Oct 15th • Already hos@ng 400+ domains • hxxp://clgang.elec@ondayfabulous.biz: 44142/4078c813508ad60acc95d0744365c68c.html • Shiping on 198.50.128.0/17 OVH prefix
- 27. Compromised GoDaddy domains • Campaign of injec@ng malicious subdomains (3LDs) under legi@mate/compromised Godaddy domains (2LDs) • 5 IPs hos@ng 800 subdomains (3LDs) over 10 days in Aug-‐Sep • Used to serve Cool exploit kit through CookieBomb aXack on compromised websites and finally drop Reveton hXp://quequero.org/2013/09/ac@ve-‐cookiebomb-‐cve-‐2013-‐2465-‐ reveton/ • Happened before in 2012 and happening again hXp://nakedsecurity.sophos.com/2012/11/23/hacked-‐go-‐daddy-‐ ransomware/
- 29. Cryptolocker CnCs • Ransomware released early September 2013 • Encrypts your files and asks for a $300 ransom to get them back • 2 ini@al Cryptolocker CnCs were picked up by the system a day before they were published on Sep 11 • xeogrhxquuubt.com • qaaepodedahnslq.org
- 30. Browlock domains • Browser-‐based ransomware targeted at countries in 3 different con@nents • Example: 194.44.49.150 hos@ng 2629 subdomains over 26 days
- 31. Browlock domains
- 32. Browlock domains (cont’d) • Browser-‐based ransomware targeted at countries in 3 different con@nents • 193.169.87.15, 196.47.100.2, over a period of 13 days, hos@ng 8978 browlock domains and domains with adult-‐ themed names that redirect to browlock
- 34. Conclusion • Ongoing research and work to increase coverage and accuracy of early detec@on of domains before they deliver aXacks • Extend coverage to shared hos@ng IPs • Effec@ve early detec@on/protec@on DNS-‐based system • Use it with other protec@on methods: AV, IDS, etc. • Experimenta@on in our lab with streaming technologies: Storm, Kava, Zeromq -‐> Complementary with DNSDB-‐based detec@on system
- 35. Contact Info • Contact me at dhia@opendns.com if you are interested in: • Asking ques@ons • Collabora@ng • Follow me on TwiXer @DhiaLite • Blogs hXp://labs.umbrella.com/author/dhia/
- 36. Thank you (Q & A)