CVE-2010-4494 in Chrome
Summary
by MITRE
Double free vulnerability in libxml2 2.7.8 and other versions, as used in Google Chrome before 8.0.552.215 and other products, allows remote attackers to cause a denial of service or possibly have unspecified other impact via vectors related to XPath handling.
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Analysis
by VulDB Data Team • 10/06/2021
The CVE-2010-4494 vulnerability represents a critical double free error in the libxml2 XML parsing library that affected numerous software products including Google Chrome versions prior to 8.0.552.215. This vulnerability resides within the XPath handling functionality of the library, which is extensively used across web browsers and applications for processing XML documents. The flaw manifests when the library processes malformed XPath expressions that trigger improper memory management operations, specifically causing the same memory block to be freed twice during the parsing process. Such double free conditions are particularly dangerous because they can lead to memory corruption that adversaries might exploit to execute arbitrary code or cause system instability.
The technical implementation of this vulnerability occurs within the XPath evaluation engine of libxml2 where certain malformed expressions trigger memory allocation and deallocation sequences that result in the same memory pointer being passed to the free function twice. This type of memory corruption vulnerability is classified under CWE-415 as double free, which is a well-known class of memory safety issues that can be exploited to manipulate program execution flow. The vulnerability's impact extends beyond simple denial of service since the memory corruption can potentially be leveraged for more sophisticated attacks. When the double free occurs during XPath processing, it creates a state where the heap memory management structures become corrupted, potentially allowing attackers to manipulate the heap layout and redirect execution flow.
The operational impact of this vulnerability is significant for web browsers and applications that rely on libxml2 for XML processing, particularly in environments where untrusted XML content is parsed. In Google Chrome's case, this vulnerability could be exploited through malicious web pages containing crafted XML with malformed XPath expressions, leading to potential remote code execution or complete browser compromise. The attack vector typically involves delivering specially crafted XML content that, when processed by the affected browser's XML parser, triggers the double free condition. This vulnerability demonstrates the importance of proper input validation and memory management in parsing libraries, as even seemingly benign XML processing can become a security risk when memory corruption occurs during parsing operations.
Mitigation strategies for CVE-2010-4494 primarily involve updating to patched versions of libxml2 and affected applications, particularly Google Chrome versions 8.0.552.215 and later. System administrators should ensure all affected software components are updated promptly, as the vulnerability can be exploited remotely without user interaction. Additional defensive measures include implementing proper input validation for XML content, using sandboxing techniques to limit the impact of potential exploitation, and monitoring for unusual memory allocation patterns. The vulnerability also highlights the importance of following secure coding practices and implementing proper memory management protocols, including the use of memory debugging tools and static analysis to identify similar issues in other libraries. Organizations should also consider implementing network-level protections and web application firewalls to detect and block malicious XML content that might trigger this vulnerability. The ATT&CK framework categorizes this vulnerability under privilege escalation and execution techniques, emphasizing the need for comprehensive security measures beyond simple patch management to protect against such memory corruption exploits.