CVE-2011-1712 in Firefox
Summary
by MITRE
The txXPathNodeUtils::getXSLTId function in txMozillaXPathTreeWalker.cpp and txStandaloneXPathTreeWalker.cpp in Mozilla Firefox before 3.5.19, 3.6.x before 3.6.17, and 4.x before 4.0.1, and SeaMonkey before 2.0.14, 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 • 05/11/2018
The vulnerability described in CVE-2011-1712 represents a critical information disclosure flaw affecting Mozilla Firefox and SeaMonkey browsers across multiple versions. This vulnerability specifically targets the XPath processing functionality within the browser's XML handling subsystem, where the txXPathNodeUtils::getXSLTId function fails to properly sanitize memory addresses when processing XSLT generate-id function calls. The flaw enables remote attackers to extract heap memory addresses through carefully crafted XML documents that invoke the XSLT generate-id XPath function, potentially exposing sensitive information about the browser's internal memory layout.
The technical implementation of this vulnerability stems from improper handling of memory addresses within the XPath tree walker implementations in Mozilla's browser engine. The txMozillaXPathTreeWalker.cpp and txStandaloneXPathTreeWalker.cpp files contain functions that process XPath expressions, particularly those involving XSLT generate-id operations. When these functions encounter XML documents containing generate-id calls, they inadvertently expose memory addresses from the heap, creating a potential information disclosure vector. This issue falls under the CWE-200 category of "Information Exposure" and represents a specific instance of memory exposure through improper data handling in the browser's XML processing pipeline. The vulnerability is particularly concerning because it allows attackers to gather memory layout information that could be leveraged in subsequent exploitation attempts.
The operational impact of this vulnerability extends beyond simple information disclosure, as the leaked memory addresses could provide attackers with valuable insights for crafting more sophisticated attacks. The exposure of heap memory addresses creates opportunities for heap spraying techniques and other exploitation methods that rely on knowing the memory layout of the target process. This vulnerability aligns with ATT&CK technique T1059.007 for "Command and Scripting Interpreter: XSLT Stylesheet," where attackers can leverage XML processing capabilities to extract information. The affected versions include Firefox 3.5.19, 3.6.x up to 3.6.17, 4.x up to 4.0.1, and SeaMonkey 2.0.14, representing a significant portion of the browser's user base at the time of discovery. Attackers could potentially use this information to bypass security mechanisms such as address space layout randomization and other exploit mitigations.
Mitigation strategies for this vulnerability involve immediate patching of affected browser versions to the patched releases that contain the necessary code fixes. The Mozilla development team addressed this issue by implementing proper memory address sanitization within the XPath tree walker functions, ensuring that heap addresses are not exposed during XSLT generate-id processing. Organizations should prioritize updating their browser installations to the latest secure versions, as the patched releases contain specific code modifications that prevent the information disclosure. Additionally, network administrators should consider implementing content filtering measures to restrict the processing of untrusted XML content when possible, though this approach provides only partial protection given the nature of the vulnerability. The fix demonstrates the importance of proper input validation and memory handling in browser security implementations, particularly in XPath and XSLT processing components that are frequently used in web applications.