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Upgrade to ProDetect Compression in Sumo Logic CSE
This detection identifies adversary use of file compression utilities (ZIP, gzip, 7z, RAR, tar) to obfuscate payloads, stage data for exfiltration, or deliver malicious archives. Key signals include compression tools spawned by unusual parent processes, self-extracting archive execution, concatenated ZIP files used to evade scanners, and shellcode compressed into registry keys. The detection focuses on behavioral anomalies such as compression utilities invoked from scripting engines, email clients, or Office applications, as well as archives extracted directly into temporary or startup directories.
MITRE ATT&CK
- Tactic
- Defense Evasion
- Technique
- T1027 Obfuscated Files or Information
- Sub-technique
- T1027.015 Compression
- Canonical reference
- https://attack.mitre.org/techniques/T1027/015/
Sumo Detection Query
_sourceCategory=windows/sysmon EventCode=1
| parse "Image=*\n" as process_image
| parse "ParentImage=*\n" as parent_image
| parse "CommandLine=*\n" as command_line
| parse "Computer=*\n" as computer
| parse "User=*\n" as user
| where matches(toLowerCase(process_image), ".*(7z\.exe|7za\.exe|7zr\.exe|winrar\.exe|rar\.exe|unrar\.exe|winzip32\.exe|winzip64\.exe|pkzip\.exe|wzzip\.exe)$")
| where matches(toLowerCase(parent_image), ".*(winword|excel|powerpnt|outlook|mshta|wscript|cscript|rundll32|regsvr32|msiexec)\.exe$")
OR matches(toLowerCase(command_line), ".*(-sfx|-mhe|-mx9|\\\\temp\\\\|\\\\appdata\\\\|\\\\programdata\\\\|\\\\users\\\\public\\\\).*")
| count by computer, user, parent_image, process_image, command_line
| where _count > 0
| order by _count descDetects Sysmon process creation logs where compression utilities are spawned by suspicious parent processes or with flags associated with self-extracting archives and encrypted compression, which are common attacker techniques to deliver or stage payloads.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate automation workflows using scripting hosts to compress log files or reports
- Software distribution systems that use self-extracting archives as normal installers
- Security products that compress quarantine or forensic archives
Other platforms for T1027.015
Testing Methodology
Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 17zip Self-Extracting Archive Creation from PowerShell
Expected signal: Sysmon Event ID 1: PowerShell spawning 7z.exe with -sfx, -p, -mhe flags. Sysmon Event ID 11: payload.exe created in C:\Users\Public\. DeviceProcessEvents in MDE.
- Test 2Concatenated ZIP Payload Creation
Expected signal: Sysmon Event ID 1: cmd.exe spawning 7z.exe twice. Sysmon Event ID 11: concatenated.zip created in C:\Temp\. Security Event 4688 if process auditing enabled.
- Test 3Linux gzip Compression of Shellcode Blob
Expected signal: Auditd syscall logs showing dd, gzip, and base64 invocations. Syslog entries for process execution. File creation event for /tmp/.hidden_payload.b64.
References (5)
- https://attack.mitre.org/techniques/T1027/015/
- https://perception-point.io/blog/analysis-of-a-phishing-campaign-using-concatenated-zip-files/
- https://www.ntt-review.jp/archive/ntttechnical.php?contents=ntr202203fa1.html
- https://thehackernews.com/2024/02/hackers-exploit-self-extracting-archive.html
- https://www.prevailion.com/darkwatchman-new-fileless-techniques/
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