CVE-2015-4511 in Firefox
Summary
by MITRE
Heap-based buffer overflow in the nestegg_track_codec_data function in Mozilla Firefox before 41.0 and Firefox ESR 38.x before 38.3 allows remote attackers to execute arbitrary code via a crafted header in a WebM video.
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Analysis
by VulDB Data Team • 10/22/2024
The vulnerability identified as CVE-2015-4511 represents a critical heap-based buffer overflow flaw discovered in Mozilla Firefox versions prior to 41.0 and Firefox ESR 38.x versions prior to 38.3. This vulnerability specifically affects the nestegg_track_codec_data function within the browser's media processing subsystem, which is responsible for handling WebM video format headers. The flaw arises when Firefox processes crafted header data within WebM files, creating a condition where attacker-controlled input can overflow heap memory buffers, potentially leading to arbitrary code execution. The vulnerability falls under the Common Weakness Enumeration category CWE-121, which describes heap-based buffer overflow conditions where insufficient bounds checking allows data to overwrite adjacent memory locations.
The technical exploitation of this vulnerability requires an attacker to craft a malicious WebM video file containing specially designed header data that triggers the buffer overflow during media parsing. When Firefox attempts to parse this malformed header, the nestegg_track_codec_data function fails to properly validate the size of incoming codec data, allowing the attacker to write beyond the allocated buffer boundaries. This overflow can overwrite critical memory structures including return addresses, function pointers, or other control data within the heap memory space. The attack vector is remote and requires no user interaction beyond viewing the malicious WebM content, making it particularly dangerous for web-based delivery mechanisms.
The operational impact of CVE-2015-4511 extends beyond simple code execution, as the heap corruption can lead to unpredictable system behavior, application crashes, or complete system compromise depending on the memory layout and exploitation techniques employed. Attackers can leverage this vulnerability to execute malicious code with the privileges of the Firefox process, potentially leading to full system compromise or data exfiltration. The vulnerability's presence in both regular Firefox releases and Extended Support Release versions indicates a widespread risk across multiple deployment scenarios. According to ATT&CK framework, this vulnerability maps to T1059.007 for command and scripting interpreter and T1068 for exploit for privilege escalation, as successful exploitation could allow attackers to establish persistent access or escalate privileges within the compromised system.
Mitigation strategies for CVE-2015-4511 primarily focus on immediate software updates to patched versions of Firefox, specifically version 41.0 or Firefox ESR 38.3 and later. Organizations should implement comprehensive patch management procedures to ensure all affected systems receive updates promptly. Additional defensive measures include implementing web content filtering solutions that can block or quarantine WebM content from untrusted sources, deploying sandboxing mechanisms to limit the impact of potential exploitation, and monitoring network traffic for suspicious WebM file transfers. Security teams should also consider implementing application whitelisting policies that restrict execution of untrusted media files, while maintaining regular security assessments to identify potential exploitation attempts. The vulnerability demonstrates the importance of proper input validation in multimedia processing libraries and highlights the critical need for robust memory safety mechanisms in browser-based media handling components.