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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_MAL_RANSOM_Revil_Oct20_1

Detects REvil ransomware

MalwareRevilSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Florian Roth (Nextron Systems)
Date
2020-10-13
Modified
2023-12-05
Score / Quality
75 / 85

What this rule detects

Detects REvil ransomware

Associated malware family: Revil.

Targets: Windows PE.

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

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
mal-ransom-revil-oct20-1.yarDetection Rule License 1.1
rule SIGNATURE_BASE_MAL_RANSOM_Revil_Oct20_1 : FILE
{
	meta:
		description = "Detects REvil ransomware"
		author = "Florian Roth (Nextron Systems)"
		id = "0c85a2cc-3487-577f-bd12-e3effd8fc811"
		date = "2020-10-13"
		modified = "2023-12-05"
		reference = "Internal Research"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/crime_ransom_revil.yar#L2-L23"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "5966c25dc1abcec9d8603b97919db57aac019e5358ee413957927d3c1790b7f4"
		hash = "f66027faea8c9e0ff29a31641e186cbed7073b52b43933ba36d61e8f6bce1ab5"
		hash = "f6857748c050655fb3c2192b52a3b0915f3f3708cd0a59bbf641d7dd722a804d"
		hash = "fc26288df74aa8046b4761f8478c52819e0fca478c1ab674da7e1d24e1cfa501"
		logic_hash = "756e49362c01abbca3208967630f09ed957e5c51956e0e5210b0167590582a82"
		score = 75
		quality = 85
		tags = "FILE"

	strings:
		$op1 = { 0f 8c 74 ff ff ff 33 c0 5f 5e 5b 8b e5 5d c3 8b }
		$op2 = { 8d 85 68 ff ff ff 50 e8 2a fe ff ff 8d 85 68 ff }
		$op3 = { 89 4d f4 8b 4e 0c 33 4e 34 33 4e 5c 33 8e 84 }
		$op4 = { 8d 85 68 ff ff ff 50 e8 05 06 00 00 8d 85 68 ff }
		$op5 = { 8d 85 68 ff ff ff 56 57 ff 75 0c 50 e8 2f }

	condition:
		uint16( 0 ) == 0x5a4d and filesize < 400KB and 2 of them or 4 of them
}

Strings (5 patterns)

IdentifierTypeValueModifiers
$op1hex{ 0f 8c 74 ff ff ff 33 c0 5f 5e 5b 8b e5 5d c3 8b }
$op2hex{ 8d 85 68 ff ff ff 50 e8 2a fe ff ff 8d 85 68 ff }
$op3hex{ 89 4d f4 8b 4e 0c 33 4e 34 33 4e 5c 33 8e 84 }
$op4hex{ 8d 85 68 ff ff ff 50 e8 05 06 00 00 8d 85 68 ff }
$op5hex{ 8d 85 68 ff ff ff 56 57 ff 75 0c 50 e8 2f }

Condition

uint16( 0 ) == 0x5a4d and filesize < 400KB and 2 of them or 4 of them

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • The file must be smaller than 400KB (a cheap guard that skips large files).
  • At least 2 patterns in the rule must match.
  • At least 4 patterns in the rule must match.

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Sample hashes

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

  • 5966c25dc1abcec9d8603b97919db57aac019e5358ee413957927d3c1790b7f4
  • f66027faea8c9e0ff29a31641e186cbed7073b52b43933ba36d61e8f6bce1ab5
  • f6857748c050655fb3c2192b52a3b0915f3f3708cd0a59bbf641d7dd722a804d
  • fc26288df74aa8046b4761f8478c52819e0fca478c1ab674da7e1d24e1cfa501

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: 0c85a2cc-3487-577f-bd12-e3effd8fc811

Tags:FILE

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