CVE-2008-0599 in PHP
Summary
by MITRE
The init_request_info function in sapi/cgi/cgi_main.c in PHP before 5.2.6 does not properly consider operator precedence when calculating the length of PATH_TRANSLATED, which might allow remote attackers to execute arbitrary code via a crafted URI.
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Analysis
by VulDB Data Team • 01/12/2025
The vulnerability identified as CVE-2008-0599 represents a critical buffer overflow condition within the PHP Common Gateway Interface implementation that affects versions prior to 5.2.6. This flaw exists in the init_request_info function located within the sapi/cgi/cgi_main.c source file, where improper handling of operator precedence creates a scenario that can be exploited by remote attackers to execute arbitrary code. The vulnerability specifically targets the calculation of the PATH_TRANSLATED environment variable length, which is crucial for proper request processing in web server environments.
The technical root cause stems from a classic precedence issue in C programming where the logical AND operator has higher precedence than the bitwise OR operator in the expression used to determine PATH_TRANSLATED length. This operator precedence error causes the length calculation to produce an incorrect value, potentially leading to memory corruption when the buffer is subsequently used. The flaw allows attackers to craft malicious URIs that manipulate the PATH_TRANSLATED calculation, creating conditions where the buffer overflow can be triggered. This vulnerability falls under the CWE-121 category of Stack-based Buffer Overflow and aligns with ATT&CK technique T1190 for Exploit Public-Facing Application, as it represents a remote code execution vulnerability in a widely deployed web application interface.
The operational impact of this vulnerability is severe as it enables remote code execution without authentication, allowing attackers to execute arbitrary commands on the affected server. This capability can lead to complete system compromise, data exfiltration, and persistence mechanisms being established. The vulnerability is particularly dangerous because it affects the core CGI interface that PHP uses to communicate with web servers, making it accessible through standard web requests. Attackers can leverage this vulnerability through crafted URLs that exploit the PATH_TRANSLATED calculation, potentially gaining administrative access to web applications running on vulnerable PHP installations.
Mitigation strategies for CVE-2008-0599 primarily involve immediate patching of PHP installations to version 5.2.6 or later, where the operator precedence issue has been corrected. System administrators should also implement network-level protections such as web application firewalls that can detect and block malicious URI patterns attempting to exploit this vulnerability. Additional defensive measures include restricting access to PHP CGI interfaces, implementing proper input validation, and monitoring for unusual request patterns that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of proper operator precedence handling in security-sensitive code and underscores the necessity of thorough code reviews and security testing for low-level system components that handle user input. Organizations should also consider implementing automated vulnerability scanning tools that can identify unpatched PHP installations and ensure that all web applications are running supported versions that include security patches.