CVE-2013-0763 in Firefox
Summary
by MITRE
Use-after-free vulnerability in Mozilla Firefox before 18.0, Firefox ESR 17.x before 17.0.1, Thunderbird before 17.0.2, Thunderbird ESR 17.x before 17.0.1, and SeaMonkey before 2.15 allows remote attackers to execute arbitrary code or cause a denial of service (heap memory corruption) via vectors related to Mesa drivers and a resized WebGL canvas.
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Analysis
by VulDB Data Team • 04/20/2021
The CVE-2013-0763 vulnerability represents a critical use-after-free flaw affecting multiple Mozilla products including Firefox, Thunderbird, and SeaMonkey. This vulnerability stems from improper memory management during WebGL canvas operations when interacting with Mesa graphics drivers, creating a dangerous condition where freed memory locations are accessed after deallocation. The flaw manifests when applications resize WebGL canvases while Mesa drivers are processing graphics operations, leading to heap memory corruption that can be exploited by remote attackers. The vulnerability is particularly concerning because it allows for arbitrary code execution or denial of service conditions, making it a significant threat to web browser security. This issue affects versions prior to Firefox 18.0, Firefox ESR 17.x before 17.0.1, Thunderbird 17.0.2, Thunderbird ESR 17.x before 17.0.1, and SeaMonkey 2.15, representing a substantial portion of the browser ecosystem at the time of discovery.
The technical root cause of this vulnerability lies in the improper handling of memory references within Mozilla's graphics rendering pipeline. When WebGL canvases are resized, the application must reallocate and reorganize memory structures to accommodate the new dimensions. However, the Mesa graphics driver integration creates a race condition where memory deallocation occurs before all references to the freed memory are properly cleared. This use-after-free condition creates a predictable memory layout that attackers can manipulate to inject malicious code into the application's memory space. The vulnerability specifically exploits the interaction between WebGL's canvas resizing functionality and Mesa's graphics processing, where the graphics driver's internal state management fails to synchronize properly with the application's memory management routines. This flaw is classified as CWE-416, representing the use of freed memory, and aligns with ATT&CK technique T1059.007 for command and scripting interpreter execution.
The operational impact of CVE-2013-0763 extends beyond simple denial of service scenarios to include full system compromise. Remote attackers can leverage this vulnerability to execute arbitrary code with the privileges of the affected application, potentially leading to complete system takeover. The heap memory corruption allows attackers to manipulate the application's execution flow, inject malicious code, or cause crashes that could be used for further exploitation. In web browser contexts, this vulnerability enables attackers to execute malicious JavaScript code that can access local files, steal user credentials, or establish persistent backdoors. The exploitation requires a user to visit a malicious website or open a specially crafted email attachment, making it particularly dangerous in social engineering campaigns. The vulnerability's impact is amplified by the widespread use of affected Mozilla products, with millions of users potentially exposed to remote code execution attacks.
Mitigation strategies for CVE-2013-0763 primarily focus on immediate patch deployment and system hardening measures. Organizations should prioritize updating all affected Mozilla products to their patched versions, including Firefox 18.0, Thunderbird 17.0.2, and SeaMonkey 2.15. Additionally, implementing security measures such as sandboxing, memory protection mechanisms, and strict content filtering can reduce the exploitation risk. Browser security enhancements including address space layout randomization, data execution prevention, and heap metadata protection can help prevent successful exploitation attempts. Network-level protections such as web application firewalls and intrusion detection systems can help detect and block exploitation attempts targeting this vulnerability. Security administrators should also consider implementing user education programs to reduce the risk of social engineering attacks that might leverage this vulnerability, as well as maintaining comprehensive monitoring and incident response procedures to quickly identify and respond to potential exploitation attempts.