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.
The MITRE CVE dictionary describes this issue as:
Find out more about CVE-2015-8994 from the MITRE CVE dictionary dictionary and NIST NVD.
Red Hat Product Security has rated this issue as having Low security impact. This issue is not currently planned to be addressed in future updates. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.
NOTE: The following CVSS v2 metrics and score provided are preliminary and subject to review.
Base Score | 4.3 |
---|---|
Base Metrics | AV:N/AC:M/Au:N/C:P/I:N/A:N |
Access Vector | Network |
Access Complexity | Medium |
Authentication | None |
Confidentiality Impact | Partial |
Integrity Impact | None |
Availability Impact | None |
NOTE: The following CVSS v3 metrics and score provided are preliminary and subject to review.
CVSS3 Base Score | 5.3 |
---|---|
CVSS3 Base Metrics | CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L |
Attack Vector | Local |
Attack Complexity | Low |
Privileges Required | Low |
User Interaction | None |
Scope | Unchanged |
Confidentiality | Low |
Integrity Impact | Low |
Availability Impact | Low |
Find out more about Red Hat support for the Common Vulnerability Scoring System (CVSS).
Platform | Package | State |
---|---|---|
Red Hat Software Collections for Red Hat Enterprise Linux | rh-php70-php | Will not fix |
Red Hat Software Collections for Red Hat Enterprise Linux | rh-php56-php | Will not fix |
Red Hat Enterprise Linux 7 | php | Not affected |
Red Hat Enterprise Linux 6 | php | Not affected |
Red Hat Enterprise Linux 5 | php53 | Not affected |
Red Hat Enterprise Linux 5 | php | Not affected |