Date: Mon, 27 Feb 2017 16:52:58 -0600 From: php-dev@...dogsoftware.net To: oss-security@...ts.openwall.com Subject: CVE Request: PHP with Zend OPCache code permission/sensitive data protection vulnerability Hello, This never got a response the first time I submitted it. PHP maintainers recognize the vulnerability, and added an undocumented non-default setting which mitigates it. Please assign a CVE if possible. To briefly summarize, in PHP SAPI's where PHP interpreters share a common parent process (eg. Apache mod_php and PHP-FPM), 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. In these scenarios, 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. AFFECTED VERSIONS: PHP7 < 7.0.14 and PHP5 < 5.6.29. Later versions are still vulnerable by default unless opcache.validate_permission=1 is enabled. AFFECTED COMPONENT: Zend OpCache VULNERABILITY TYPE: Code permission/sensitive information disclosure IMPACT: Cross-user compromise of PHP web applications in shared hosting environments. Let me know if more details are needed, and feel free to contact me privately if proof of concept is needed. REFERENCES: http://marc.info/?l=php-internals&m=147921016724565&w=2 https://bugs.php.net/bug.php?id=69090 http://seclists.org/oss-sec/2016/q4/343 -- php-dev at coydogsoftware dot net
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