A vulnerability has been identified in PHP, which could be exploited by local attackers to bypass security restrictions. This issue is due to a race condition between the time that "open_basedir" access controls for a symbolic link are verified and the time the requested file is accessed by certain functions, which could be exploited by malicious users to gain unauthorized access to restricted files via a PHP script containing "symlink()", "mkdir()", "unlink()", and "fopen()" calls.
It is also possible to bypass "safe_mode" and "open_basedir" restrictions via a malicious path and a NULL byte before a ";" in a "session_save_path" argument, followed by an allowed path.
Credits
Vulnerabilities reported by Stefan Esser and Maksymilian Arciemowicz
ChangeLog
2006-10-04 : Initial release
2007-02-06 : Updated Advisory
Vulnerability Management
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