Vulnerability identifier: #VU40285

Vulnerability risk: High

CVSSv3.1: 8.8 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2015-6834

CWE-ID: CWE-20

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
PHP
Universal components / Libraries / Scripting languages

Vendor: PHP Group

Description

The vulnerability allows a remote non-authenticated attacker to execute arbitrary code.

Multiple use-after-free vulnerabilities in PHP before 5.4.45, 5.5.x before 5.5.29, and 5.6.x before 5.6.13 allow remote attackers to execute arbitrary code via vectors related to (1) the Serializable interface, (2) the SplObjectStorage class, and (3) the SplDoublyLinkedList class, which are mishandled during unserialization. <a href="http://cwe.mitre.org/data/definitions/502.html">CWE-502: Deserialization of Untrusted Data</a>

Mitigation
Install update from vendor's website.

Vulnerable software versions

PHP: 5.5.0 - 5.5.28, 5.6.0 - 5.6.12

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External links
http://php.net/ChangeLog-5.php
http://www.debian.org/security/2015/dsa-3358
http://www.securityfocus.com/bid/76649
http://www.securitytracker.com/id/1033548
http://bugs.php.net/bug.php?id=70172
http://bugs.php.net/bug.php?id=70365
http://bugs.php.net/bug.php?id=70366
http://security.gentoo.org/glsa/201606-10

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.