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SEKOIA_Infostealer_Win_Stormkitty_Exfil_Urls

Detect the open-source StormKitty spyware by looking for the github path

MalwareStormkittySEKOIA.IO CommunityDetection Rule License 1.1Compiles with YARA-X
Author
Sekoia.io
Date
2022-04-20
Modified
2024-12-19
Score / Quality
75 / 80

What this rule detects

Detect the open-source StormKitty spyware by looking for the github path

Associated malware family: Stormkitty.

Targets: Windows PE.

It defines 3 patterns (3 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
infostealer-win-stormkitty-exfil-urls.yarDetection Rule License 1.1
rule SEKOIA_Infostealer_Win_Stormkitty_Exfil_Urls : FILE
{
	meta:
		description = "Detect the open-source StormKitty spyware by looking for the github path"
		author = "Sekoia.io"
		id = "d3b6e778-85da-4ab6-bc98-921897677485"
		date = "2022-04-20"
		modified = "2024-12-19"
		reference = "https://github.com/SEKOIA-IO/Community"
		source_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/yara_rules/infostealer_win_stormkitty_exfil_urls.yar#L1-L19"
		license_url = "https://github.com/SEKOIA-IO/Community/blob/a438a5901a211c2abdf75da9c93921ef187473d1/LICENSE.md"
		logic_hash = "ccf0efe9ccba8e37bc19fa241e2d7698b1a798a3e8026b1b6930452b8a8ba9b4"
		score = 75
		quality = 80
		tags = "FILE"
		version = "1.0"
		classification = "TLP:CLEAR"

	strings:
		$s1 = "https://github.com/LimerBoy/StormKitty" ascii
		$telegram = "https://api.telegram.org" wide
		$discord = "https://cdn.discordapp.com" wide

	condition:
		uint16( 0 ) == 0x5A4D and all of them and ( #telegram > 3 or #discord > 3 )
}

Strings (3 patterns)

IdentifierTypeValueModifiers
$s1text"https://github.com/LimerBoy/StormKitty"ascii
$telegramtext"https://api.telegram.org"wide
$discordtext"https://cdn.discordapp.com"wide

Condition

uint16( 0 ) == 0x5A4D and all of them and ( #telegram > 3 or #discord > 3 )

In plain words (Heuristic)

  • The file must start with “MZ” — a Windows executable (PE).
  • All patterns in the rule must match.
  • Pattern $telegram must occur > 3 times.
  • Pattern $discord must occur > 3 times.

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References

Licence & attribution

Author: Sekoia.io

Source repository: SEKOIA.IO Community @ a438a5901a

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: d3b6e778-85da-4ab6-bc98-921897677485

Metadata

version1.0
classificationTLP:CLEAR

Tags:FILE

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