#VU9957 Deserialization of untrusted data in PHP - CVE-2017-12934

Vulnerability identifier: #VU9957

Vulnerability risk: High

CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2017-12934

CWE-ID: CWE-502

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
PHP
Universal components / Libraries / Scripting languages

Vendor: PHP Group

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a heap use after free while unserializing untrusted data, related to the zval_get_type function in Zend/zend_types.h in ext/standard/var_unserializer.re. A remote attacker can trigger a use-after-free condition and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation
The vendor has issued the following versions to address this vulnerability: 7.0.21, 7.1.7

Vulnerable software versions

PHP: 7.0.0 - 7.0.20, 7.1.0 - 7.1.6

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External links
https://php.net/ChangeLog-7.php
https://bugs.php.net/bug.php?id=74101

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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.