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Sigma - Generic Signatures for SIEM Systems
- 1. Sigma Make Security Monitoring Great Again Florian Roth,January 2017
- 2. Agenda § Conventional Threat Detection § Traces of Modern Threats § Lack of Standardization and Exchange § Sigma – The Open Source Approach § Examples § Outlook: Roadmap, RFI, Support
- 3. Conventional Threat Detection Alert triggers focus mainly on the following events: § Network Events § Lower ISO-OSI Layers 1-4 § Port Scans, Ping Sweeps,Xmas Scan, Smurf Attack ;) § Failed Logons § Multiple Failed Logons § Multiple Failed Logons followed by Successful Logon (^The single most worn-out correlation example)
- 5. Modern Threat Priorities Malware § Distribution § Exfiltration of Secrets / Ransom Advanced Persistent Threats § Exfiltration of Secrets § Large-Scale and Persistent Compromise § Stealth
- 6. Traces of Modern Threats Malware § Distribution > Port Scans, Sweeps, Failed Logons § Exfiltration of Secrets / Ransom > C2 Connect, Ransom Note Advanced Persistent Threats § Exfiltration of Secrets > C2 Connect, P2P Communication § Large-Scale and Persistent Compromise > PTH, PTT, Rootkits, Backdoors, Built-in (WMI, Sticky Key), Dual User Admin Tools, Remote Access Tools § Stealth > Valid Accounts, Golden Ticket, DNS/ICMP Exfil, Covert Channel
- 7. Detection of Modern Threats Malware - Nothing new needed § Smart Antivirus alert processing § Report on C2 traffic in proxy blocks and IDS/IPS alerts § Backup/Restore in case of ransomware § Analyze and report on samples with Sandbox solutions
- 8. Detection of Modern Threats Advanced Persistent Threats § Same as for malware threats (cause malware is used in links of the kill chain) § Malware-less Threats § Web Shells > web server logs, process monitoring (e.g. Sysmon, Carbon Black …) § PTH, PTT > Smart Windows audit log inspection, process monitoring § Dual Use Tools, Scripts > Process monitoring,Application control (AppLocker), PowerShell / WMI monitoring § Backdoors with built-in tools > Process monitoring (integrity analysis – sig/hash), Registry monitoring, PowerShell / WMI monitoring
- 9. Problem § Conventional threat detection covers the only the most obvious malicious activity and some extras § Is already struggling with false positives § Lack of visibility in application layers § Lack of signatures for threats in application layers This is where Sigma steps in
- 10. § Generic signature format to describe relevant events in log files § Open repository for sigma signatures § Set of converters that generate searches/queries for different SIEM / log management systems
- 11. Signature Format – Example 1
- 12. Signature Format – Example 2
- 13. § Describe your once discovered detection method in Sigma to make it sharable § Share the signature in the appendix of your analysis along with file hashes and C2 servers § Share the signature in threat intel communities - e.g. via MISP § Provide Sigma signatures for malicious behavior in your application (Error messages, access violations, manipulations) § Integrate a new log into your SIEM and check the Sigma repository for available rules § Develop an experimental detection method, write a Sigma rule, share it and ask for feedback § Write a rule converter for your custom log analysis tool and process new Sigma rules automatically § Provide a free or commercial feed for Sigma signatures
- 14. Outlook § Public Release – Q1/2017 § Complete proposal for specification § Reasonable example signature set § Roadmap 2017 § First converters for ElasticSearch queries and Splunk searches § Support needed § Rule ideas for different log sources § QRadar,ArcSight, Carbon Black
- 15. Sigma Make Security Monitoring Great Again Florian Roth,January 2017