CVE-2007-4255 in PHP
Summary
by MITRE
Buffer overflow in the mSQL extension in PHP 5.2.3 allows context-dependent attackers to execute arbitrary code via a long first argument to the msql_connect function.
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Analysis
by VulDB Data Team • 09/29/2024
The vulnerability identified as CVE-2007-4255 represents a critical buffer overflow flaw within the mSQL extension of PHP version 5.2.3. This issue stems from inadequate input validation and memory management within the msql_connect function, which processes the first argument provided by attackers. The flaw exists in the way PHP handles string inputs when establishing connections to mSQL databases through its deprecated mSQL extension, creating an exploitable condition where malicious input can overwrite adjacent memory locations.
The technical implementation of this vulnerability falls under CWE-121, which classifies buffer overflow conditions where insufficient bounds checking allows attackers to write beyond allocated memory buffers. The mSQL extension in PHP 5.2.3 fails to properly validate the length of the first argument passed to msql_connect, enabling attackers to craft specially formatted input that exceeds the allocated buffer size. This overflow can overwrite critical memory segments including return addresses, function pointers, and other control data structures necessary for proper program execution.
From an operational perspective, this vulnerability creates a significant risk for systems running PHP 5.2.3 with the mSQL extension enabled, particularly in web environments where user input might be processed through database connection functions. Attackers can leverage this flaw to execute arbitrary code with the privileges of the web server process, potentially leading to complete system compromise. The context-dependent nature of the attack means that successful exploitation requires the attacker to have some level of control over the input parameters passed to the msql_connect function, typically through web application interfaces or other input vectors that ultimately reach this vulnerable function.
The attack vector for CVE-2007-4255 aligns with techniques documented in the ATT&CK framework under T1059 for command and script injection, where attackers can inject malicious payloads that trigger the buffer overflow condition. Systems are particularly vulnerable when PHP applications accept user input without proper sanitization and pass it directly to msql_connect functions. The exploitation process typically involves crafting a long string input that triggers the buffer overflow, potentially allowing attackers to overwrite the instruction pointer and redirect execution flow to malicious code. Organizations should note that this vulnerability was particularly dangerous because it affected widely deployed web applications and could be exploited through common web application attack patterns.
Mitigation strategies for this vulnerability include immediate patching of PHP installations to versions that address the buffer overflow issue, disabling the deprecated mSQL extension entirely, and implementing proper input validation and sanitization measures throughout applications. Security teams should also consider implementing network segmentation, web application firewalls, and monitoring systems to detect potential exploitation attempts. The vulnerability demonstrates the importance of maintaining up-to-date software components and avoiding deprecated database extensions that may contain unpatched security flaws. Organizations should conduct thorough security assessments to identify all instances of the vulnerable mSQL extension and ensure complete removal or proper patching of affected systems.