CVE-2011-1202 in Chrome
Summary
by MITRE
The xsltGenerateIdFunction function in functions.c in libxslt 1.1.26 and earlier, as used in Google Chrome before 10.0.648.127 and other products, allows remote attackers to obtain potentially sensitive information about heap memory addresses via an XML document containing a call to the XSLT generate-id XPath function.
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Analysis
by VulDB Data Team • 10/19/2021
The vulnerability identified as CVE-2011-1202 represents a significant information disclosure flaw within the libxslt library implementation of the XSLT generate-id function. This issue affects versions 1.1.26 and earlier, creating a pathway for remote attackers to extract sensitive heap memory address information through carefully crafted XML documents. The vulnerability specifically targets the xsltGenerateIdFunction function located in functions.c, which is a core component of the XSLT processing engine used across multiple applications including Google Chrome versions prior to 10.0.648.127. The flaw stems from inadequate memory management practices during the processing of XPath function calls, particularly those involving memory address exposure.
The technical implementation of this vulnerability exploits the inherent behavior of the generate-id XPath function, which is designed to create unique identifiers for XML nodes. However, when processing malicious XML content containing calls to this function, the libxslt library fails to properly sanitize or obscure memory addresses that are inadvertently exposed during the function execution. This occurs because the implementation does not adequately mask or randomize the memory addresses that are internally generated and potentially accessible through the function's output. The vulnerability manifests when the XSLT processor encounters an XML document with a generate-id function call, causing the system to leak memory addresses that could be used by attackers to perform more sophisticated attacks such as heap spraying or address space layout randomization (ASLR) bypass techniques.
From an operational impact perspective, this vulnerability creates serious security implications for systems relying on libxslt for XML processing, particularly web browsers and server applications that handle untrusted XML content. The information disclosure aspect allows attackers to gain insights into the memory layout of the affected systems, which can significantly aid in developing more targeted attacks. According to CWE-200, this vulnerability falls under information exposure, specifically exposing memory addresses that can be leveraged for privilege escalation or bypassing security mechanisms. The attack vector is particularly concerning because it requires only the ability to submit XML content to the affected system, making it accessible to remote attackers who can exploit this through web applications, email clients, or any other interface that processes XML data.
The exploitation of this vulnerability aligns with techniques described in the ATT&CK framework under the information gathering phase, where adversaries collect information about the target system's memory layout to facilitate subsequent attacks. Security professionals should note that this vulnerability demonstrates the importance of proper memory management in XML processing libraries and highlights the risks associated with insufficient input validation in XPath function implementations. The vulnerability also underscores the broader category of memory safety issues that affect XML processors and emphasizes the need for robust sanitization of function outputs. Organizations should prioritize updating their libxslt implementations to versions 1.1.27 or later, where the memory address leakage has been properly addressed through improved memory management practices and output sanitization techniques. Additionally, implementing proper XML input validation and content filtering mechanisms can provide additional defense-in-depth measures against similar vulnerabilities that may exist in other XML processing components.