CVE-2011-1938 in PHP
Summary
by MITRE
Stack-based buffer overflow in the socket_connect function in ext/sockets/sockets.c in PHP 5.3.3 through 5.3.6 might allow context-dependent attackers to execute arbitrary code via a long pathname for a UNIX socket.
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Analysis
by VulDB Data Team • 06/13/2024
The vulnerability identified as CVE-2011-1938 represents a critical stack-based buffer overflow affecting PHP versions 5.3.3 through 5.3.6. This flaw resides within the socket_connect function located in the ext/sockets/sockets.c file of the PHP source code, specifically impacting the handling of UNIX socket pathnames. The vulnerability manifests when the system processes a socket connection request with an excessively long pathname, creating conditions that allow attackers to overwrite adjacent memory locations on the stack. This particular flaw falls under CWE-121 Stack-based Buffer Overflow, which is classified as a fundamental memory safety issue that enables arbitrary code execution when attacker-controlled data exceeds the allocated buffer size.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with a pathway to execute arbitrary code within the context of the PHP process. When a maliciously crafted pathname exceeds the buffer boundaries, the overflow can overwrite return addresses, function pointers, and other critical stack data, potentially allowing an attacker to redirect program execution flow. This vulnerability is particularly dangerous in web server environments where PHP processes user-supplied input, as it can be exploited through web-based attacks targeting socket connection functions. The context-dependent nature of this vulnerability means that exploitation requires specific conditions, including the ability to influence the pathname parameter passed to socket_connect, but once achieved, the consequences are severe and can lead to complete system compromise.
The exploitation of CVE-2011-1938 aligns with ATT&CK technique T1059.007 for command and scripting interpreter, specifically targeting the execution of arbitrary code through memory corruption vulnerabilities. This attack vector is particularly relevant in environments where PHP serves as a web application framework, as attackers can leverage the vulnerability through web applications that utilize socket functionality or through direct exploitation of vulnerable PHP scripts. The vulnerability demonstrates the importance of input validation and proper buffer management in interpreted languages, as the flaw exists in the core socket handling functionality that many applications rely upon for network communication. Security practitioners should note that this vulnerability requires no special privileges to exploit, as it operates within the context of the PHP process itself, making it a significant concern for web applications that process untrusted input through socket operations.
Mitigation strategies for this vulnerability involve immediate patching of affected PHP installations to versions beyond 5.3.6, where the buffer overflow has been corrected through proper bounds checking and input validation. Additionally, administrators should implement input sanitization measures that validate the length of socket pathnames before processing them through socket_connect functions, implementing defensive programming practices that align with secure coding guidelines. Network segmentation and privilege separation can help limit the potential impact of successful exploitation, while monitoring for unusual socket connection patterns may help detect exploitation attempts. The vulnerability serves as a reminder of the critical importance of maintaining up-to-date software versions and implementing comprehensive security testing procedures that include memory safety analysis, particularly for interpreted languages that interface with system-level operations. Organizations should also consider implementing application whitelisting and runtime protection mechanisms to detect and prevent exploitation attempts targeting similar buffer overflow vulnerabilities in their PHP applications.