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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_SUSP_LNK_Follina_Jun22

Detects LNK files with suspicious Follina/CVE-2022-30190 strings

Suspicious / huntingSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Paul Hager
Date
2022-06-02
Modified
2026-05-15
Score / Quality
75 / 85

What this rule detects

Detects LNK files with suspicious Follina/CVE-2022-30190 strings

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

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
susp-lnk-follina-jun22.yarDetection Rule License 1.1
rule SIGNATURE_BASE_SUSP_LNK_Follina_Jun22 : CVE_2022_30190 FILE
{
	meta:
		description = "Detects LNK files with suspicious Follina/CVE-2022-30190 strings"
		author = "Paul Hager"
		id = "d331d584-2ab3-5275-b435-6129c7291417"
		date = "2022-06-02"
		modified = "2026-05-15"
		reference = "https://twitter.com/gossithedog/status/1531650897905950727"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/gen_doc_follina.yar#L244-L262"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		logic_hash = "0b63bb266b968987b2b5a83c9429e96acbd57e12178e4f5fd5894b23d1aaa237"
		score = 75
		quality = 85
		tags = "CVE-2022-30190, FILE"

	strings:
		$sa1 = "msdt.exe" ascii wide
		$sa2 = "msdt " ascii wide
		$sa3 = "ms-msdt:" ascii wide
		$sb = "IT_BrowseForFile=" ascii wide

	condition:
		filesize < 5KB and uint16( 0 ) == 0x004c and uint32( 4 ) == 0x00021401 and 1 of ( $sa* ) and $sb
}

Strings (4 patterns)

IdentifierTypeValueModifiers
$sa1text"msdt.exe"ascii wide
$sa2text"msdt "ascii wide
$sa3text"ms-msdt:"ascii wide
$sbtext"IT_BrowseForFile="ascii wide

Condition

filesize < 5KB and uint16( 0 ) == 0x004c and uint32( 4 ) == 0x00021401 and 1 of ( $sa* ) and $sb

In plain words (Heuristic)

  • The file must be smaller than 5KB (a cheap guard that skips large files).
  • At least 1 patterns in ( $sa* ) must match.
  • Pattern $sb must be present.

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References

Licence & attribution

Author: Paul Hager

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: d331d584-2ab3-5275-b435-6129c7291417

Tags:CVE_2022_30190FILE

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