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Wenke Lee David Dagon Georgia Institute of Technology. Malware Repository Overview. Overview. How malware is collected and shared now Malfease’s service-oriented repository
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Wenke Lee David Dagon Georgia Institute of Technology Malware Repository Overview
Overview • How malware is collected and shared now • Malfease’s service-oriented repository • Support for malware analysis, e.g., signature generation, and evaluation of intrusion/anomaly detection/prevention systems, etc. • Automated unpacking
Current Practices • Numerous private, semi-public malware collections • Need “trust” to join • “Too much sharing” often seen as competitive disadvantage • Analysis not shared • Incomplete collections: reflect sensor bias • Darknet-based collection • IRC surveillance • Honeypot-based collection
Shortcomings • Malware authors know and exploit weaknesses in data collection • Illuminating sensors • “Mapping Internet Sensors with Probe Response Attacks”, Bethencourt, et al., Usenix 2005 • Automated victims updates • E.g., via botnets
Solution:Service-Oriented Repository • Malfease uses hub-and-spoke model • Hub is central collection of malware • Spokes are analysis partners • Hub: • Malware, indexing, search • Static analysis: header extraction, icons, libraries • Metainfo: longitudinal AV scan results • Spoke: • E.g., dynamic analysis, unpacking, signatures, etc.
Malware Repo Requirements • Malware repos should not: • Help illuminate sensors • Serve as a malware distribution site • Malware repo should: • Help automate analysis of malware flood • Coordinate different analysts (RE gurus, Snort rule writers, etc.)
Approaches • Repository allows upload of samples • Downloads restricted to classes of users • Repository provides binaries and analysis • Automated unpacking • Win32 PE Header analysis • Longitudinal detection data • What did the AV tool know, and when did it know it? • Malware similarity analysis, family tree • Etc.
Repository User Classes • Unknown users • Scripts, random users, even bots • Humans • CAPTCHA-verified • Authenticated Users • Known trusted contributors
Repository Access Control • Unknown users • Upload; view aggregate statistics • Humans • Upload; download analysis of their samples • Authenticated Users • Upload; download all; access analysis
Static Analysis Example Note search ability
Dynamic Analysis Unpacked binary Available for Download, Along with asm version
Malware: Why Pack? • Reduced malware size • Obfuscation transformation • Opaque binaries prevent pattern analysis • Invalid PE32 headers complicate RE • Increases response time • Unpacking often requires specialized skill sets
Results • Improved AV detection 10-40% improved AV detection on “old” stuff 5.2K Samples Claimed VX AV Scan 6K very old Samples Unpacking 0.8K Claimed “OK” 42 are now claimed VX AV ReScan
Plan for Cyber-TA • Evaluation of various signature generation schemes • Development of new schemes • Development of signature ensemble scheme - automatically combine the attributes of signatures from different generation schemes • Evaluation of intrusion/anomaly detection systems • E.g., automatically generating mimicry/blending attacks based on malware
Conclusion • Service-oriented repository • Support research in malware analysis and intrusion/anomaly detection/prevention • See malfease.oarci.net for details • Credits • David Dagon • Paul Vixie • Paul Royal • Mitch Halpin