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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_MAL_WIPER_Caddywiper_Mar22_1

Detects CaddyWiper malware

MalwareCaddywiperSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Florian Roth (Nextron Systems)
Date
2022-03-15
Modified
2023-12-05
Score / Quality
85 / 85

What this rule detects

Detects CaddyWiper malware

Associated malware family: Caddywiper.

Targets: Windows PE.

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

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
mal-wiper-caddywiper-mar22-1.yarDetection Rule License 1.1
rule SIGNATURE_BASE_MAL_WIPER_Caddywiper_Mar22_1 : FILE
{
	meta:
		description = "Detects CaddyWiper malware"
		author = "Florian Roth (Nextron Systems)"
		id = "83495a0d-a295-5ec7-9761-ce79918e1034"
		date = "2022-03-15"
		modified = "2023-12-05"
		reference = "https://twitter.com/ESETresearch/status/1503436420886712321?s=20&t=xh8JK6fEmRIrnqO7Ih_PNg"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/apt_ua_caddywiper.yar#L2-L22"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "1e87e9b5ee7597bdce796490f3ee09211df48ba1d11f6e2f5b255f05cc0ba176"
		hash = "a294620543334a721a2ae8eaaf9680a0786f4b9a216d75b55cfd28f39e9430ea"
		hash = "ea6a416b320f32261da8dafcf2faf088924f99a3a84f7b43b964637ea87aef72"
		hash = "f1e8844dbfc812d39f369e7670545a29efef6764d673038b1c3edd11561d6902"
		logic_hash = "0d0278596010953e7068979c92a33dc0ace1bfa94979077412128d1ca756f834"
		score = 85
		quality = 85
		tags = "FILE"

	strings:
		$op1 = { ff 55 94 8b 45 fc 50 ff 55 f8 8a 4d ba 88 4d ba 8a 55 ba 80 ea 01 }
		$op2 = { 89 45 f4 83 7d f4 00 74 04 eb 47 eb 45 6a 00 8d 95 1c ff ff ff 52 }
		$op3 = { 6a 20 6a 02 8d 4d b0 51 ff 95 68 ff ff ff 85 c0 75 0a e9 4e 02 00 00 }
		$op4 = { e9 67 01 00 00 83 7d f4 05 74 0a e9 5c 01 00 00 e9 57 01 00 00 8d 45 98 50 6a 20 }

	condition:
		uint16( 0 ) == 0x5a4d and filesize < 50KB and 3 of them or all of them
}

Strings (4 patterns)

IdentifierTypeValueModifiers
$op1hex{ ff 55 94 8b 45 fc 50 ff 55 f8 8a 4d ba 88 4d ba 8a 55 ba 80 ea 01 }
$op2hex{ 89 45 f4 83 7d f4 00 74 04 eb 47 eb 45 6a 00 8d 95 1c ff ff ff 52 }
$op3hex{ 6a 20 6a 02 8d 4d b0 51 ff 95 68 ff ff ff 85 c0 75 0a e9 4e 02 00 00 }
$op4hex{ e9 67 01 00 00 83 7d f4 05 74 0a e9 5c 01 00 00 e9 57 01 00 00 8d 45 98 50 6a 20 }

Condition

uint16( 0 ) == 0x5a4d and filesize < 50KB and 3 of them or all of them

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • The file must be smaller than 50KB (a cheap guard that skips large files).
  • All patterns in the rule must match.
  • At least 3 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).

  • 1e87e9b5ee7597bdce796490f3ee09211df48ba1d11f6e2f5b255f05cc0ba176
  • a294620543334a721a2ae8eaaf9680a0786f4b9a216d75b55cfd28f39e9430ea
  • ea6a416b320f32261da8dafcf2faf088924f99a3a84f7b43b964637ea87aef72
  • f1e8844dbfc812d39f369e7670545a29efef6764d673038b1c3edd11561d6902

Licence & attribution

Author: Florian Roth (Nextron Systems)

Source repository: Signature Base (Florian Roth / Nextron) @ 94a1c48d7a

Licence: Detection Rule License 1.1 (repository licence)

Original rule

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

Rule id: 83495a0d-a295-5ec7-9761-ce79918e1034

Tags:FILE

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