rule EXPL_RAR_Archive_with_Path_Traversal_Aug25 { meta: description = "Detects RAR archives abused for path traversal like CVE-2025-8088 and CVE-2025-6218" reference = "https://www.welivesecurity.com/en/eset-research/update-winrar-tools-now-romcom-and-others-exploiting-zero-day-vulnerability/#the-discovery-of-cve-2025-8088" author = "Arnim Rupp (Nextron Systems)" date = "2025-08-11" score = 70 hash = "2a8fafa01f6d3863c87f20905736ebab28d6a5753ab708760c0b6cf3970828c3" hash = "dfab2f25c9d870f30bbc4abb873d155cf4904ece536714fb9cd32b2e0126dfab" hash = "107f3d1fe28b67397d21a6acca5b6b35def1aeb62a67bc10109bd73d567f9806" strings: // Only look for the users Autostart folder because the most effective attack method // Use \ and / to handle archives created on Windows and Linux $s1 = "..\\\\..\\AppData\\Roaming\\Microsoft\\Windows\\Start Menu" $s2 = "..//../AppData/Roaming/Microsoft/Windows/Start Menu" // CVE-2025-6218: $s3 = "/.. /.. /AppData/Roaming/Microsoft/Windows/Start Menu/" condition: 1 of ( $s* ) and ( uint16(0) == 0x4B50 // Yes, Winrar can chocke on ZIPs or int32(0) == 0x21726152 // RAR ) }