PHP Version 5 Hash Collision Form Parameter Parsing Remote DoS

medium Nessus Plugin ID 57557
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The version of PHP running on the remote host is affected by a denial of service vulnerability.


The remote web server uses a version of PHP that is affected by a hash collision denial of service. A flaw exists in the way PHP generates hash tables for user-supplied values. By sending a small number of specially crafted POST requests to a web server that uses PHP, an attacker can take advantage of this flaw to cause a denial of service condition.

Note that this plugin only tests PHP version 5, and it only runs if 'Report paranoia' is set to 'Paranoid' and the 'Perform thorough tests' setting is enabled.


Upgrade to PHP 5.3.9 or later.

See Also

Plugin Details

Severity: Medium

ID: 57557

File Name: php_5_hash_collision_dos.nbin

Version: 1.70

Type: remote

Family: CGI abuses

Published: 1/16/2012

Updated: 4/20/2021

Dependencies: php_version.nasl, webmirror.nasl

Configuration: Enable paranoid mode

Risk Information


Risk Factor: Medium

Score: 5.7


Risk Factor: Medium

Base Score: 5

Temporal Score: 4.1

Vector: AV:N/AC:L/Au:N/C:N/I:N/A:P

Temporal Vector: E:F/RL:OF/RC:C

Vulnerability Information

CPE: cpe:/a:php:php

Required KB Items: www/PHP, Settings/ParanoidReport

Excluded KB Items: Settings/disable_cgi_scanning

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 1/11/2012

Vulnerability Publication Date: 12/28/2011

Exploitable With

Core Impact

Metasploit (Hashtable Collisions)

Reference Information

CVE: CVE-2011-4885

BID: 51193

CERT: 903934