CVE-2012-5838 in Firefox
Summary
by MITRE
The copyTexImage2D implementation in the WebGL subsystem in Mozilla Firefox before 17.0, Thunderbird before 17.0, and SeaMonkey before 2.14 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption and application crash) via large image dimensions.
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Analysis
by VulDB Data Team • 04/19/2021
The vulnerability identified as CVE-2012-5838 represents a critical heap-based buffer overflow in the WebGL subsystem of Mozilla Firefox and related products. This flaw exists within the copyTexImage2D function implementation which processes texture data during WebGL operations. The vulnerability stems from inadequate input validation and bounds checking when handling image dimensions, particularly when processing large texture data structures. Attackers can exploit this weakness by crafting malicious WebGL content that specifies excessively large width and height parameters, causing the application to allocate insufficient memory for texture storage while simultaneously attempting to write beyond allocated boundaries. The flaw manifests as a memory corruption condition that can be leveraged for arbitrary code execution or forced application termination through denial of service attacks. This vulnerability affects a broad range of Mozilla products including Firefox versions prior to 17.0, Thunderbird versions before 17.0, and SeaMonkey versions before 2.14, indicating a widespread impact across the Mozilla ecosystem.
The technical exploitation of this vulnerability involves the manipulation of WebGL texture operations where the copyTexImage2D function fails to properly validate the dimensions of incoming image data. When large values are passed for width and height parameters, the implementation calculates memory requirements without proper overflow checks, leading to heap corruption when the application attempts to allocate memory for the texture. This memory corruption can occur in multiple ways including stack smashing, heap spraying, or overwrite of critical data structures within the application's memory space. The vulnerability is classified as a heap-based buffer overflow under CWE-122, which specifically addresses insufficient restriction of operations within the bounds of a memory buffer. The flaw demonstrates characteristics of a classic memory safety issue where the application fails to enforce proper bounds checking before memory allocation and subsequent data copying operations. This type of vulnerability is particularly dangerous in browser contexts where the attack surface includes WebGL APIs that are frequently accessed by web content.
The operational impact of CVE-2012-5838 extends beyond simple application crashes to potentially enable full remote code execution capabilities. When exploited successfully, this vulnerability allows attackers to inject and execute arbitrary code within the context of the affected browser process, potentially leading to complete system compromise. The memory corruption can be leveraged through various attack vectors including drive-by downloads, malicious websites, or compromised web content that triggers WebGL operations with malicious parameters. The denial of service aspect of this vulnerability can be used to repeatedly crash applications, disrupting user productivity and potentially enabling persistent availability attacks. From an attacker's perspective, the vulnerability is particularly attractive because WebGL APIs are commonly used in modern web applications, making exploitation relatively easy to achieve through standard web browsing activities. The vulnerability also aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter, specifically JavaScript-based attacks, where attackers can use WebGL functionality to bypass security controls and execute malicious code.
Mitigation strategies for CVE-2012-5838 primarily focus on immediate patch deployment and application updates to versions that contain proper bounds checking and input validation for WebGL texture operations. Users should immediately upgrade to Firefox 17.0, Thunderbird 17.0, or SeaMonkey 2.14 and later versions where the vulnerability has been addressed through code modifications that enforce proper dimension validation and memory allocation checks. Organizations should implement network-level protections including web content filtering and sandboxing measures to prevent access to potentially malicious WebGL content. Browser security configurations should be hardened by disabling WebGL when not required for business operations, though this may impact legitimate web applications. Additionally, security monitoring should be enhanced to detect unusual WebGL operations or memory allocation patterns that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper input validation in graphics APIs and highlights the need for comprehensive security testing of multimedia and graphics subsystems within web browsers. Security teams should also consider implementing automated patch management systems to ensure rapid deployment of security updates across all affected Mozilla products within their environments.