CVE-2012-3970 in Firefox
Summary
by MITRE
Use-after-free vulnerability in the nsTArray_base::Length function in Mozilla Firefox before 15.0, Firefox ESR 10.x before 10.0.7, Thunderbird before 15.0, Thunderbird ESR 10.x before 10.0.7, and SeaMonkey before 2.12 allows remote attackers to execute arbitrary code or cause a denial of service (heap memory corruption) via vectors involving movement of a requiredFeatures attribute from one SVG document to another.
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Analysis
by VulDB Data Team • 12/31/2024
This vulnerability exists within the nsTArray_base::Length function of Mozilla Firefox and related applications including Thunderbird and SeaMonkey. The issue represents a classic use-after-free condition that occurs when memory is accessed after it has been freed, creating opportunities for memory corruption and potential code execution. The vulnerability specifically manifests when handling SVG document elements, particularly during the movement of a requiredFeatures attribute from one document to another. This particular vector involves the manipulation of array-based data structures within the browser's rendering engine, where improper memory management leads to exploitable conditions.
The technical flaw stems from inadequate bounds checking and memory lifecycle management within the nsTArray_base implementation. When an SVG document element undergoes attribute movement operations, the underlying array structure may be freed while references to it still exist in memory. This creates a situation where subsequent operations on the freed memory can either overwrite critical data structures or redirect execution flow through controlled memory corruption. The vulnerability is particularly dangerous because it operates within the browser's core rendering pipeline, allowing attackers to manipulate memory contents that govern how graphical elements are processed and displayed.
Operational impact of this vulnerability extends beyond simple denial of service to include complete system compromise. Remote attackers can leverage the heap memory corruption to execute arbitrary code with the privileges of the affected browser process, potentially leading to full system compromise. The vulnerability's exploitation requires specific conditions involving SVG document manipulation, making it less common than some other browser exploits but still highly concerning given the widespread use of these applications. The memory corruption can manifest as crashes, data corruption, or more insidiously, as stealthy code execution that may go undetected for extended periods.
Mitigation strategies should focus on immediate patching of all affected versions, as the vulnerability affects multiple Mozilla products across different release channels. Organizations should prioritize updating Firefox 15.0, Thunderbird 15.0, and SeaMonkey 2.12 releases, along with their respective ESR versions. Additionally, implementing network-based protections such as content filtering and sandboxing can provide additional defense layers. The vulnerability aligns with CWE-416, which describes use-after-free conditions, and represents a typical attack pattern found in the ATT&CK framework under the technique of code injection through memory corruption. Browser vendors should implement stricter memory management practices and enhanced bounds checking in array operations to prevent similar issues from occurring in future releases.