Risk | Medium |
Patch available | YES |
Number of vulnerabilities | 1 |
CVE-ID | CVE-2015-8994 |
CWE-ID | CWE-264 |
Exploitation vector | Network |
Public exploit | N/A |
Vulnerable software Subscribe |
PHP Universal components / Libraries / Scripting languages |
Vendor | PHP Group |
This security bulletin contains one medium risk vulnerability.
EUVDB-ID: #VU39590
Risk: Medium
CVSSv3.1:
CVE-ID: CVE-2015-8994
CWE-ID:
CWE-264 - Permissions, Privileges, and Access Controls
Exploit availability: No
DescriptionThe vulnerability allows a remote authenticated user to execute arbitrary code.
An issue was discovered in PHP 5.x and 7.x, when the configuration uses apache2handler/mod_php or php-fpm with OpCache enabled. With 5.x after 5.6.28 or 7.x after 7.0.13, the issue is resolved in a non-default configuration with the opcache.validate_permission=1 setting. The vulnerability details are as follows. In PHP SAPIs where PHP interpreters share a common parent process, Zend OpCache creates a shared memory object owned by the common parent during initialization. Child PHP processes inherit the SHM descriptor, using it to cache and retrieve compiled script bytecode ("opcode" in PHP jargon). Cache keys vary depending on configuration, but filename is a central key component, and compiled opcode can generally be run if a script's filename is known or can be guessed. Many common shared-hosting configurations change EUID in child processes to enforce privilege separation among hosted users (for example using mod_ruid2 for the Apache HTTP Server, or php-fpm user settings). In these scenarios, the default Zend OpCache behavior defeats script file permissions by sharing a single SHM cache among all child PHP processes. PHP scripts often contain sensitive information: Think of CMS configurations where reading or running another user's script usually means gaining privileges to the CMS database.
MitigationInstall update from vendor's website.
Vulnerable software versionsPHP: 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.28, 5.4.0 - 5.4.45, 5.5.0 - 5.5.37, 5.6.0 - 5.6.29, 7.0.0 - 7.0.14
http://marc.info/?l=php-internals&m=147876797317925&w=2
http://marc.info/?l=php-internals&m=147921016724565&w=2
http://openwall.com/lists/oss-security/2017/02/28/1
http://seclists.org/oss-sec/2016/q4/343
http://seclists.org/oss-sec/2017/q1/520
http://bugs.php.net/bug.php?id=69090
http://ma.ttias.be/a-better-way-to-run-php-fpm/
Can this vulnerability be exploited remotely?
Is there known malware, which exploits this vulnerability?