CVE-2012-0449 in Firefox
Summary
by MITRE
Mozilla Firefox before 3.6.26 and 4.x through 9.0, Thunderbird before 3.1.18 and 5.0 through 9.0, and SeaMonkey before 2.7 allow remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via a malformed XSLT stylesheet that is embedded in a document.
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Analysis
by VulDB Data Team • 01/31/2018
This vulnerability represents a critical memory corruption flaw in Mozilla's browser and email client software that affects multiple versions across different product lines. The issue stems from improper handling of malformed XSLT (Extensible Stylesheet Language Transformations) stylesheets that can be embedded within web documents or email messages. When these maliciously crafted XSLT elements are processed by the affected software, they trigger memory corruption conditions that can lead to application instability and potential code execution. The vulnerability specifically impacts Firefox versions prior to 3.6.26 and 4.x through 9.0, Thunderbird versions before 3.1.18 and 5.0 through 9.0, and SeaMonkey versions before 2.7, creating a widespread attack surface across the Mozilla ecosystem.
The technical root cause of this vulnerability lies in the insufficient input validation and memory management within the XSLT processing engine of these applications. When a malformed XSLT stylesheet is encountered during document parsing, the software fails to properly validate the structure and content of the stylesheet before attempting to process it. This lack of proper bounds checking and memory allocation validation creates opportunities for attackers to craft malicious XSLT content that can overwrite memory locations or manipulate pointers in ways that lead to unpredictable behavior. The vulnerability manifests as heap-based buffer overflows or use-after-free conditions that can corrupt the application's memory space and potentially allow for arbitrary code execution.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable remote code execution attacks. Attackers can leverage this flaw by embedding malicious XSLT content within HTML documents or email messages that are then processed by vulnerable applications. When users visit compromised websites or open malicious email attachments, the vulnerable software automatically processes the embedded XSLT content, triggering the memory corruption. This creates a sophisticated attack vector that can be delivered through various channels including phishing campaigns, compromised websites, or malicious email attachments, making it particularly dangerous for end users who may not be aware of the underlying threat.
Security professionals should note that this vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and represents a classic example of memory safety issues that have been increasingly targeted in modern exploit campaigns. The attack pattern follows typical adversary tactics described in the MITRE ATT&CK framework under techniques such as T1203 (Exploitation for Client Execution) and T1059 (Command and Scripting Interpreter), where attackers leverage application vulnerabilities to execute malicious code. Organizations should prioritize immediate patching of affected systems and implement network-level controls to block suspicious XSLT content, particularly in email gateways and web proxies. The vulnerability also highlights the importance of input sanitization and the need for robust memory management practices in complex software applications that process untrusted content from external sources.
Mitigation strategies should include immediate deployment of vendor patches and updates, implementation of web application firewalls to filter malicious XSLT content, and user education regarding suspicious email attachments and websites. Additionally, security teams should consider implementing sandboxing techniques for web browsing activities and monitoring for unusual memory allocation patterns that may indicate exploitation attempts. The vulnerability demonstrates the critical importance of maintaining up-to-date security patches and implementing defense-in-depth strategies to protect against sophisticated attacks that exploit memory corruption vulnerabilities in widely used software applications.