CVE-2011-1944 in HTTP Server
Summary
by MITRE
Integer overflow in xpath.c in libxml2 2.6.x through 2.6.32 and 2.7.x through 2.7.8, and libxml 1.8.16 and earlier, allows context-dependent attackers to cause a denial of service (crash) and possibly execute arbitrary code via a crafted XML file that triggers a heap-based buffer overflow when adding a new namespace node, related to handling of XPath expressions.
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Analysis
by VulDB Data Team • 09/13/2024
The vulnerability identified as CVE-2011-1944 represents a critical integer overflow flaw within the libxml2 library that affects versions ranging from 2.6.x through 2.6.32 and 2.7.x through 2.7.8, alongside libxml 1.8.16 and earlier versions. This issue stems from improper handling of XPath expressions during namespace node addition operations, creating a heap-based buffer overflow condition that can be exploited by context-dependent attackers. The flaw resides specifically within the xpath.c file of the affected libraries, making it a fundamental component of the XML processing pipeline that applications rely upon for parsing and evaluating XPath queries.
The technical implementation of this vulnerability involves an integer overflow condition that occurs when processing XPath expressions containing crafted XML data structures. When the library attempts to add a new namespace node during XPath evaluation, the integer overflow causes memory allocation calculations to wrap around, resulting in insufficient buffer sizing. This leads to heap-based buffer overflows that can manifest as program crashes or potentially allow arbitrary code execution. The vulnerability's exploitation requires a carefully crafted XML file that triggers the specific code path involving namespace handling within XPath expressions, making it context-dependent rather than universally exploitable. According to CWE standards, this maps to CWE-190 Integer Overflow or Wraparound, which falls under the broader category of CWE-129 Improper Validation of Array Index, specifically targeting memory safety vulnerabilities in XML processing libraries.
The operational impact of CVE-2011-1944 extends beyond simple denial of service conditions to potentially enable remote code execution in vulnerable environments. Systems that process untrusted XML data through libxml2 libraries become susceptible to this vulnerability, particularly web applications, XML-based services, and any software that relies on XML parsing for configuration or data exchange. The vulnerability affects a wide range of applications including web servers, content management systems, and enterprise applications that utilize XML processing capabilities. Attackers can leverage this flaw to crash applications, causing denial of service, or in more sophisticated scenarios, potentially execute malicious code with the privileges of the affected process. The vulnerability's presence in both libxml2 and libxml 1.8.16 and earlier versions creates an extensive attack surface across multiple software ecosystems, making it a high-priority remediation target for organizations.
Mitigation strategies for CVE-2011-1944 require immediate patching of affected libraries to the latest stable versions that contain the necessary fixes for integer overflow conditions. Organizations should prioritize updating their libxml2 installations to versions 2.7.9 or later, where the integer overflow has been addressed through proper bounds checking and memory allocation validation. Additionally, implementing input validation measures that restrict XML content processing and employing XML parsers with enhanced security features can provide additional layers of protection. Security monitoring should include detection of malformed XML processing patterns that might indicate exploitation attempts, and network segmentation can help limit the potential impact of successful attacks. The ATT&CK framework categorizes this vulnerability under T1210 Exploitation of Remote Services, where attackers leverage library vulnerabilities to achieve system compromise, making it essential for security teams to monitor for indicators of compromise related to XML processing failures and unauthorized code execution attempts.