#VU16119 Integer underflow in PHP - CVE-2015-4021

Vulnerability identifier: #VU16119

Vulnerability risk: Low

CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2015-4021

CWE-ID: CWE-191

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 cause DoS condition on the target system.

The weakness exists due to the phar_parse_tarfile function in ext/phar/tar.c in PHP before 5.4.41, 5.5.x before 5.5.25, and 5.6.x before 5.6.9 does not verify that the first character of a filename is different from the character. A remote attacker can trigger integer underflow and memory corruption)via a crafted entry in a tar archive and cause the service to crash.

Mitigation
Install update from vendor's website.

Vulnerable software versions

PHP: 5.4.0 - 5.4.40, 5.5.0 - 5.5.24, 5.6.0 - 5.6.8

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External links
https://bugs.php.net/bug.php?id=69453

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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.