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TRELLIX_ARC_Chimera_Recordedtv_Modified

Rule to detect the modified version of RecordedTV.ms found in the Operation Skeleton

MalwareRecordedTVTrellix Advanced Research CenterApache License 2.0Compiles with YARA-X
Author
Marc Rivero | McAfee ATR Team
Date
2020-04-21
Modified
2020-08-14
Score / Quality
75 / 70

What this rule detects

Rule to detect the modified version of RecordedTV.ms found in the Operation Skeleton

Associated malware family: RecordedTV.

Targets: Windows PE.

It defines 5 patterns (4 text, 1 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

chimera-recordedtv-modified.yarApache License 2.0
rule TRELLIX_ARC_Chimera_Recordedtv_Modified : TROJAN FILE
{
	meta:
		description = "Rule to detect the modified version of RecordedTV.ms found in the Operation Skeleton"
		author = "Marc Rivero | McAfee ATR Team"
		id = "b0969713-41a4-550c-9545-f02783fa8d02"
		date = "2020-04-21"
		modified = "2020-08-14"
		reference = "https://medium.com/@cycraft_corp/taiwan-high-tech-ecosystem-targeted-by-foreign-apt-group-5473d2ad8730"
		source_url = "https://github.com/advanced-threat-research/Yara-Rules//blob/1919562a59f190bda60c982424f6a24c542ee3e0/APT/APT_operation_skeleton.yar#L1-L33"
		license_url = "https://github.com/advanced-threat-research/Yara-Rules//blob/1919562a59f190bda60c982424f6a24c542ee3e0/LICENSE"
		hash = "66f13964c87fc6fe093a9d8cc0de0bf2b3bdaea9564210283fdb97a1dde9893b"
		logic_hash = "7165779b66999259a079fa68f898c5f9fb634adcb9d249366d321dff1014184b"
		score = 75
		quality = 70
		tags = "TROJAN, FILE"
		rule_version = "v1"
		malware_type = "trojan"
		malware_family = "Trojan:W32/RecordedTV"
		actor_type = "Apt"
		actor_group = "Unknown"

	strings:
		$byte = { C0 0E 5B C3 }
		$s1 = "Encrypted file:  CRC failed in %s (password incorrect ?)" fullword wide
		$s2 = "EBorland C++ - Copyright 1999 Inprise Corporation" fullword ascii
		$s3 = " MacOS file type:  %c%c%c%c  ; " fullword wide
		$s4 = "rar.lng" fullword ascii

	condition:
		uint16( 0 ) == 0x5a4d and filesize < 900KB and all of them
}

Strings (5 patterns)

IdentifierTypeValueModifiers
$bytehex{ C0 0E 5B C3 }
$s1text"Encrypted file: CRC failed in %s (password incorrect ?)"fullword wide
$s2text"EBorland C++ - Copyright 1999 Inprise Corporation"fullword ascii
$s3text" MacOS file type: %c%c%c%c ; "fullword wide
$s4text"rar.lng"fullword ascii

Condition

uint16( 0 ) == 0x5a4d and filesize < 900KB and all of them

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • The file must be smaller than 900KB (a cheap guard that skips large files).
  • All patterns in the rule must match.

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References

Sample hashes

Hashes of samples the author lists in the rule's meta (look them up in your threat-intelligence platform).

  • 66f13964c87fc6fe093a9d8cc0de0bf2b3bdaea9564210283fdb97a1dde9893b

Licence & attribution

Author: Marc Rivero | McAfee ATR Team

Source repository: Trellix Advanced Research Center @ 1919562a59

Licence: Apache License 2.0 (repository licence)

Original rule

Mirrored via YARA Forge 20260927, which prefixes rule names with the source and adds normalised meta fields.

Rule id: b0969713-41a4-550c-9545-f02783fa8d02

Metadata

rule_versionv1
malware_typetrojan
malware_familyTrojan:W32/RecordedTV
actor_typeApt
actor_groupUnknown

Tags:TROJANFILE