CVE-2010-4008 in Chrome
Summary
by MITRE
libxml2 before 2.7.8, as used in Google Chrome before 7.0.517.44, Apple Safari 5.0.2 and earlier, and other products, reads from invalid memory locations during processing of malformed XPath expressions, which allows context-dependent attackers to cause a denial of service (application crash) via a crafted XML document.
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Analysis
by VulDB Data Team • 03/18/2021
The vulnerability identified as CVE-2010-4008 represents a critical memory safety issue within the libxml2 library version 2.7.7 and earlier, which was widely adopted across numerous web browsers and applications. This flaw specifically manifests during the processing of malformed XPath expressions, where the library fails to properly validate memory access patterns when encountering malformed input. The vulnerability affects major web browsers including Google Chrome versions prior to 7.0.517.44, Apple Safari 5.0.2 and earlier versions, along with numerous other products that rely on libxml2 for XML parsing operations. The issue stems from improper handling of invalid memory references during XPath expression evaluation, creating a scenario where attackers can manipulate XML documents to trigger memory access violations.
The technical implementation of this vulnerability involves the libxml2 library's XPath evaluation engine failing to properly validate memory pointers when processing malformed XPath expressions within XML documents. When an application processes XML content containing crafted XPath expressions, the library attempts to access memory locations that have not been properly allocated or initialized. This leads to memory access violations that result in application crashes and denial of service conditions. The vulnerability is classified as a memory access error under CWE-125, which describes out-of-bounds read conditions where programs access memory locations beyond the bounds of allocated buffers. The flaw operates at the intersection of memory safety and XML processing, where improper input validation allows attackers to manipulate the execution flow of the parsing engine through carefully crafted XML constructs.
From an operational perspective, this vulnerability poses significant risks to web applications and browsers that process untrusted XML content. The context-dependent nature of the attack means that exploitation requires specific conditions where malformed XML documents are processed by affected applications. Attackers can craft XML documents containing malicious XPath expressions that, when parsed by vulnerable versions of libxml2, trigger memory access violations leading to application crashes. This denial of service scenario can be particularly impactful in web environments where applications must process XML content from various sources, potentially allowing attackers to disrupt service availability for legitimate users. The vulnerability aligns with ATT&CK technique T1210, which involves exploitation of remote services through memory corruption vulnerabilities, and represents a classic example of how XML processing libraries can become attack vectors.
The remediation strategy for CVE-2010-4008 involves immediate upgrade of libxml2 to version 2.7.8 or later, which includes proper memory validation and bounds checking for XPath expression processing. Additionally, applications should implement input validation and sanitization measures to prevent processing of malformed XML content from untrusted sources. Security practitioners should also consider implementing network-level protections such as web application firewalls that can detect and block suspicious XML content patterns. The vulnerability highlights the importance of keeping XML processing libraries up to date and demonstrates how seemingly minor memory safety issues can lead to significant security implications in widely used software components. Organizations should conduct comprehensive vulnerability assessments to identify all systems using affected versions of libxml2 and ensure proper patch management procedures are in place to prevent exploitation of similar memory safety vulnerabilities.