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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_REGEORG_Tuneller_Generic

No description has been set in the source file - Signature Base

GenericSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Mandiant
Date
2021-12-20
Modified
2023-12-05
Score / Quality
75 / 85

What this rule detects

No description has been set in the source file - Signature Base

It defines 8 patterns (8 text, 0 hex, 0 regex).

Summary generated from the rule's metadata and condition.

Rule source

regeorg-tuneller-generic.yarDetection Rule License 1.1
rule SIGNATURE_BASE_REGEORG_Tuneller_Generic : FILE
{
	meta:
		description = "No description has been set in the source file - Signature Base"
		author = "Mandiant"
		id = "a87979b7-2732-5a32-b3f3-a815a58b6589"
		date = "2021-12-20"
		modified = "2023-12-05"
		reference = "https://www.mandiant.com/resources/unc3524-eye-spy-email"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/webshell_regeorg.yar#L1-L20"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		hash = "ba22992ce835dadcd06bff4ab7b162f9"
		logic_hash = "1657928875c3cd2d5bf774929b0497d78f0211b321f8a4138cc9b8c80b9f99d6"
		score = 75
		quality = 85
		tags = "FILE"
		date_modified = "2021-12-20"

	strings:
		$s1 = "System.Net.IPEndPoint"
		$s2 = "Response.AddHeader"
		$s3 = "Request.InputStream.Read"
		$s4 = "Request.Headers.Get"
		$s5 = "Response.Write"
		$s6 = "System.Buffer.BlockCopy"
		$s7 = "Response.BinaryWrite"
		$s8 = "SocketException soex"

	condition:
		filesize < 1MB and 7 of them
}

Strings (8 patterns)

IdentifierTypeValueModifiers
$s1text"System.Net.IPEndPoint"
$s2text"Response.AddHeader"
$s3text"Request.InputStream.Read"
$s4text"Request.Headers.Get"
$s5text"Response.Write"
$s6text"System.Buffer.BlockCopy"
$s7text"Response.BinaryWrite"
$s8text"SocketException soex"

Condition

filesize < 1MB and 7 of them

In plain words (Heuristic)

  • The file must be smaller than 1MB (a cheap guard that skips large files).
  • At least 7 patterns in the rule 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).

  • ba22992ce835dadcd06bff4ab7b162f9

Licence & attribution

Author: Mandiant

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: a87979b7-2732-5a32-b3f3-a815a58b6589

Metadata

date_modified2021-12-20

Tags:FILE