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YARA · Signature Base (Florian Roth / Nextron)

SIGNATURE_BASE_VULN_PHP_Hack_Backdoored_Zlib_Zerodium_Mar21_1

Detects backdoored PHP zlib version

GenericSignature Base (Florian Roth / Nextron)Detection Rule License 1.1Compiles with YARA-X
Author
Florian Roth (Nextron Systems)
Date
2021-03-29
Modified
2023-12-05
Score / Quality
75 / 85

What this rule detects

Detects backdoored PHP zlib version

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

Summary generated from the rule's metadata and condition.

Rule source

Download .yar
vuln-php-hack-backdoored-zlib-zerodium-mar21-1.yarDetection Rule License 1.1
rule SIGNATURE_BASE_VULN_PHP_Hack_Backdoored_Zlib_Zerodium_Mar21_1 : FILE
{
	meta:
		description = "Detects backdoored PHP zlib version"
		author = "Florian Roth (Nextron Systems)"
		id = "5e0ab8f8-776a-52b0-b5be-ff1d34bccfd1"
		date = "2021-03-29"
		modified = "2023-12-05"
		reference = "https://www.bleepingcomputer.com/news/security/phps-git-server-hacked-to-add-backdoors-to-php-source-code/"
		source_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/yara/vul_php_zlib_backdoor.yar#L2-L15"
		license_url = "https://github.com/Neo23x0/signature-base/blob/94a1c48d7ab499879287ff611dfe7f9c56376030/LICENSE"
		logic_hash = "74bfd9e12cb7671cde953d361a2adeb9388edd9b2aab0f9ce04dce0d433561dc"
		score = 75
		quality = 85
		tags = "FILE"

	strings:
		$x1 = "REMOVETHIS: sold to zerodium, mid 2017" fullword ascii
		$x2 = "HTTP_USER_AGENTT" ascii fullword

	condition:
		filesize < 3000KB and all of them
}

Strings (2 patterns)

IdentifierTypeValueModifiers
$x1text"REMOVETHIS: sold to zerodium, mid 2017"fullword ascii
$x2text"HTTP_USER_AGENTT"ascii fullword

Condition

filesize < 3000KB and all of them

In plain words (Heuristic)

  • The file must be smaller than 3000KB (a cheap guard that skips large files).
  • All patterns in the rule must match.

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References

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: 5e0ab8f8-776a-52b0-b5be-ff1d34bccfd1

Tags:FILE

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