CVE-2015-0825 in Firefox
Summary
by MITRE
Stack-based buffer underflow in the mozilla::MP3FrameParser::ParseBuffer function in Mozilla Firefox before 36.0 allows remote attackers to obtain sensitive information from process memory via a malformed MP3 file that improperly interacts with memory allocation during playback.
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Analysis
by VulDB Data Team • 03/10/2022
The vulnerability identified as CVE-2015-0825 represents a critical stack-based buffer underflow in Mozilla Firefox's MP3 frame parser implementation. This flaw exists within the mozilla::MP3FrameParser::ParseBuffer function, which is responsible for processing MP3 audio files during playback operations. The vulnerability manifests when Firefox encounters malformed MP3 files that exploit improper memory allocation handling during the parsing process, potentially leading to information disclosure through memory corruption. The issue affects versions of Firefox prior to 36.0, making it a significant concern for users running older browser versions. This type of vulnerability falls under the CWE-121 category of stack-based buffer overflow conditions, though the specific underflow aspect suggests a more nuanced memory manipulation scenario where insufficient bounds checking allows data to be written beyond allocated stack space.
The technical exploitation of this vulnerability occurs during the playback of MP3 files when the parser encounters malformed data structures that cause improper memory handling. When Firefox attempts to parse an MP3 frame with corrupted or unexpected data, the MP3FrameParser function fails to properly validate input boundaries, leading to a situation where memory adjacent to the stack buffer becomes overwritten or accessed improperly. This memory corruption can result in sensitive information leakage from process memory, including potentially confidential data such as cryptographic keys, session tokens, or other application state information that may be stored in adjacent memory locations. The underflow condition specifically indicates that the parser attempts to access memory locations that are positioned before the allocated buffer, rather than after it, which can cause unpredictable behavior and information disclosure.
From an operational impact perspective, this vulnerability enables remote attackers to execute information disclosure attacks against Firefox users without requiring any user interaction beyond visiting a malicious website or opening a crafted MP3 file. The attack vector is particularly dangerous because it leverages the common use case of audio file playback, making it difficult for users to distinguish between legitimate and malicious content. Successful exploitation can lead to the exposure of sensitive process memory contents, potentially compromising user sessions, stored credentials, or other confidential data that may be present in the application's memory space. This vulnerability directly impacts the confidentiality aspect of the CIA triad and can be classified under the ATT&CK technique T1059 for execution through malicious code, specifically targeting memory corruption to achieve unauthorized information access.
Mitigation strategies for CVE-2015-0825 primarily focus on updating to Firefox version 36.0 or later, where the vulnerability has been addressed through improved bounds checking and memory validation in the MP3 parsing implementation. Organizations should prioritize immediate deployment of the patched Firefox version across all systems to eliminate exposure to this information disclosure vulnerability. Additionally, implementing network-based security controls such as content filtering and sandboxing mechanisms can provide additional defense-in-depth layers. Security teams should also consider monitoring for suspicious MP3 file downloads or playback attempts, particularly in environments where users may encounter untrusted content. The fix implemented by Mozilla likely involved strengthening input validation in the MP3 frame parser to ensure proper boundary checking during memory allocation and access operations, preventing the underflow condition that previously allowed memory corruption and information disclosure.