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COD3NYM_MAL_NET_Limecrypter_Runpe_Jan24

Detects LimeCrypter RunPE module. LimeCrypter is an open source .NET based crypter and loader commonly used by threat actors

MalwareCod3nym detection-rulesDetection Rule License 1.1Compiles with YARA-X
Author
Jonathan Peters
Date
2024-01-16
Score / Quality
80 / 80

What this rule detects

Detects LimeCrypter RunPE module. LimeCrypter is an open source .NET based crypter and loader commonly used by threat actors

Targets: Windows PE.

It defines 6 patterns (2 text, 4 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

mal-net-limecrypter-runpe-jan24.yarDetection Rule License 1.1
rule COD3NYM_MAL_NET_Limecrypter_Runpe_Jan24 : FILE
{
	meta:
		description = "Detects LimeCrypter RunPE module. LimeCrypter is an open source .NET based crypter and loader commonly used by threat actors"
		author = "Jonathan Peters"
		id = "06ecd638-0102-5762-b363-fdc390dda04b"
		date = "2024-01-16"
		modified = "2024-01-16"
		reference = "https://github.com/NYAN-x-CAT/Lime-Crypter/tree/master"
		source_url = "https://github.com/cod3nym/detection-rules//blob/86a04c4594cb48895192aad4af164f21f568c136/yara/dotnet/mal/mal_net_limecrypter_runpe.yar#L1-L22"
		license_url = "https://github.com/cod3nym/detection-rules//blob/86a04c4594cb48895192aad4af164f21f568c136/LICENSE.md"
		hash = "bcc8c679acfc3aabf22ebdb2349b1fabd351a89fd23a716d85154049d352dd12"
		logic_hash = "b01a68c60d62cf94ef16340316acb9b96d1e671c372559b86a8e6a5d8e80f7d9"
		score = 80
		quality = 80
		tags = "FILE"

	strings:
		$op1 = { 1F 1A 58 1F 1A 58 28 }
		$op2 = { 20 B3 00 00 00 8D ?? 00 00 01 13 ?? 11 ?? 16 20 02 00 01 00 }
		$op3 = { 11 0? 11 0? 20 00 30 00 00 1F 40 28 ?? 00 00 06 }
		$op4 = { 6E 20 FF 7F 00 00 6A FE 02 }
		$s1 = "RawSecurityDescriptor" ascii
		$s2 = "CommonAce" ascii

	condition:
		uint16( 0 ) == 0x5a4d and all of ( $s* ) and 2 of ( $op* )
}

Strings (6 patterns)

IdentifierTypeValueModifiers
$op1hex{ 1F 1A 58 1F 1A 58 28 }
$op2hex{ 20 B3 00 00 00 8D ?? 00 00 01 13 ?? 11 ?? 16 20 02 00 01 00 }
$op3hex{ 11 0? 11 0? 20 00 30 00 00 1F 40 28 ?? 00 00 06 }
$op4hex{ 6E 20 FF 7F 00 00 6A FE 02 }
$s1text"RawSecurityDescriptor"ascii
$s2text"CommonAce"ascii

Condition

uint16( 0 ) == 0x5a4d and all of ( $s* ) and 2 of ( $op* )

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • All patterns in ( $s* ) must match.
  • At least 2 patterns in ( $op* ) 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).

  • bcc8c679acfc3aabf22ebdb2349b1fabd351a89fd23a716d85154049d352dd12

Licence & attribution

Author: Jonathan Peters

Source repository: Cod3nym detection-rules @ 86a04c4594

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: 06ecd638-0102-5762-b363-fdc390dda04b

Tags:FILE