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EMBEERESEARCH_Win_Medusa_Bytecodes

Medusa Bytecodes

MalwareMedusaEmbee ResearchDetection Rule License 1.1Compiles with YARA-X
Author
Matthew @ Embee_Research
Date
2023-08-27
Modified
2024-03-03
Score / Quality
75 / 75

What this rule detects

Medusa Bytecodes

Associated malware family: Medusa.

It defines 2 patterns (1 text, 1 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
win-medusa-bytecodes.yarDetection Rule License 1.1
rule EMBEERESEARCH_Win_Medusa_Bytecodes
{
	meta:
		description = "Medusa Bytecodes"
		author = "Matthew @ Embee_Research"
		id = "48b659f8-cd26-540a-89b6-6349f8d21e8f"
		date = "2023-08-27"
		modified = "2024-03-03"
		reference = "https://github.com/embee-research/Yara-detection-rules/"
		source_url = "https://github.com/embee-research/Yara-detection-rules//blob/ac56d6f6fd2a30c8cb6e5c0455d6519210a8b0f4/Rules/win_medusa_dotnet_bytecodes.yar#L1-L17"
		license_url = "N/A"
		hash = "a1211549b4e1a7befd953d03b4d929b3dc9f25ec6c1bc9c05ae92a0ec08fb77c"
		logic_hash = "aa01afd6981af99625a9fca93e512cc00931aca18e55c5cb6dee11efb9ea2968"
		score = 75
		quality = 75
		tags = ""

	strings:
		$s1 = {1F ?? 8D ?? ?? ?? 01 25 16 72 ?? ?? ?? 70 A2 25 17 72 ?? ?? ?? 70 28 ?? ?? ?? 0A A2 25 18 20 ?? ?? ?? 00 13 04 12 04 28 ?? ?? ?? 0A A2 25 19 20 ?? ?? ?? 00 13 ?? 12 }
		$s2 = "\\Medusa\\obj\\Release\\Medusa.pdb" ascii

	condition:
		$s1 or $s2
}

Strings (2 patterns)

IdentifierTypeValueModifiers
$s1hex{1F ?? 8D ?? ?? ?? 01 25 16 72 ?? ?? ?? 70 A2 25 17 72 ?? ?? ?? 70 28 ?? ?? ?? 0A A2 25 18 20 ?? ?? ?? 00 13 04 12 04 28 ?? ?? ?? 0A A2 25 19 20 ?? ?? ?? 00 13 …
$s2text"\\Medusa\\obj\\Release\\Medusa.pdb"ascii

Condition

$s1 or $s2

In plain words (Heuristic)

  • Pattern $s1 must be present.
  • Pattern $s2 must be present.

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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).

  • a1211549b4e1a7befd953d03b4d929b3dc9f25ec6c1bc9c05ae92a0ec08fb77c

Licence & attribution

Author: Matthew @ Embee_Research

Source repository: Embee Research @ ac56d6f6fd

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: 48b659f8-cd26-540a-89b6-6349f8d21e8f

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