YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_SUSP_ZIP_LNK_Phishattachment_Pattern_Jun22_1

Detects suspicious tiny ZIP files with phishing attachment characteristics

Suspicious / huntingSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X

Author: Florian Roth (Nextron Systems)
Date: 2022-06-23
Modified: 2023-12-05
Score / Quality: 65 / 85

What this rule detects

Detects suspicious tiny ZIP files with phishing attachment characteristics

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

Summary generated from the rule's metadata and condition.

Rule source

Download .yar

susp-zip-lnk-phishattachment-pattern-jun22-1.yarDetection Rule License 1.1

rule SIGNATURE_BASE_SUSP_ZIP_LNK_Phishattachment_Pattern_Jun22_1 : FILE
{
	meta:
		description = "Detects suspicious tiny ZIP files with phishing attachment characteristics"
		author = "Florian Roth (Nextron Systems)"
		id = "3537c4ea-a51d-5100-97d7-71a24da5ff43"
		date = "2022-06-23"
		modified = "2023-12-05"
		reference = "Internal Research"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/gen_phish_attachments.yar#L2-L21"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "4edb41f4645924d8a73e7ac3e3f39f4db73e38f356bc994ad7d03728cd799a48"
		hash = "c4fec375b44efad2d45c49f30133efbf6921ce82dbb2d1a980f69ea6383b0ab4"
		hash = "9c70eeac97374213355ea8fa019a0e99e0e57c8efc43daa3509f9f98fa71c8e4"
		hash = "ddc20266e38a974a28af321ab82eedaaf51168fbcc63ac77883d8be5200dcaf9"
		hash = "b59788ae984d9e70b4f7f5a035b10e6537063f15a010652edd170fc6a7e1ea2f"
		logic_hash = "2ff398379e3d8112991eeacd99bf9d3bafbf3e9266f012d2539d6b2661d5969e"
		score = 65
		quality = 85
		tags = "FILE"

	strings:
		$sl1 = ".lnk"

	condition:
		uint16( 0 ) == 0x4b50 and filesize < 2KB and $sl1 in ( filesize -256 .. filesize )
}

Strings (1 patterns)

Identifier	Type	Value	Modifiers
$sl1	text	".lnk"

Condition

uint16( 0 ) == 0x4b50 and filesize < 2KB and $sl1 in ( filesize -256 .. filesize )

In plain words (Heuristic)

The file must start with “PK” — a ZIP archive (also Office Open XML, JAR, APK).
The file must be smaller than 2KB (a cheap guard that skips large files).
Pattern $sl1 must be found within the range filesize -256 .. filesize.

Test this rule in your browser

Drop a file to scan it with this rule using YARA-X compiled to WebAssembly. Nothing is uploaded.

Drop a file here or click to chooseScanned locally with YARA-X. Files up to 200 MB.

Open in editor

Sample hashes

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

4edb41f4645924d8a73e7ac3e3f39f4db73e38f356bc994ad7d03728cd799a48
c4fec375b44efad2d45c49f30133efbf6921ce82dbb2d1a980f69ea6383b0ab4
9c70eeac97374213355ea8fa019a0e99e0e57c8efc43daa3509f9f98fa71c8e4
ddc20266e38a974a28af321ab82eedaaf51168fbcc63ac77883d8be5200dcaf9
b59788ae984d9e70b4f7f5a035b10e6537063f15a010652edd170fc6a7e1ea2f

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: 3537c4ea-a51d-5100-97d7-71a24da5ff43

Tags:FILE

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