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.
References
Link | Resource |
---|---|
http://marc.info/?l=php-internals&m=147876797317925&w=2 | Mailing List |
http://marc.info/?l=php-internals&m=147921016724565&w=2 | Mailing List |
http://openwall.com/lists/oss-security/2017/02/28/1 | Mailing List |
http://seclists.org/oss-sec/2016/q4/343 | Mailing List Third Party Advisory |
http://seclists.org/oss-sec/2017/q1/520 | Mailing List Third Party Advisory |
https://bugs.php.net/bug.php?id=69090 | Exploit Issue Tracking |
https://ma.ttias.be/a-better-way-to-run-php-fpm/ | Exploit Technical Description Third Party Advisory |
History
No history.
MITRE Information
Status: PUBLISHED
Assigner: mitre
Published: 2017-03-02T06:00:00
Updated: 2017-03-02T05:57:01
Reserved: 2017-02-28T00:00:00
Link: CVE-2015-8994
JSON object: View
NVD Information
Status : Analyzed
Published: 2017-03-02T06:59:00.167
Modified: 2022-08-16T13:16:57.330
Link: CVE-2015-8994
JSON object: View
Redhat Information
No data.
CWE