HKTL_CobaltStrike_Beacon_XOR_Strings

rule HKTL_CobaltStrike_Beacon_XOR_Strings {
   meta:
      author = "Elastic"
      description = "Identifies XOR'd strings used in Cobalt Strike Beacon DLL"
      reference = "https://www.elastic.co/blog/detecting-cobalt-strike-with-memory-signatures"
      date = "2021-03-16"
      modified = "2026-05-26"
      /* Used for beacon config decoding in THOR */
      xor_s1 = "%02d/%02d/%02d %02d:%02d:%02d"
      xor_s2 = "Started service %s on %s"
      xor_s3 = "%s as %s\\%s: %d"
      id = "359160a8-cf1c-58a8-bf7f-c09a8d661308"
   strings:
      $s1 = "%02d/%02d/%02d %02d:%02d:%02d" xor(0x01-0xff)
      $s2 = "Started service %s on %s" xor(0x01-0xff)
      $s3 = "%s as %s\\%s: %d" xor(0x01-0xff)

      $fp1 = "MalwareRemovalTool" ascii wide
      $fp2 = "advanced malware removal tool" ascii wide
   condition:
      2 of ($s*) and not 1 of ($fp*)
}