CVE-2014-0045 in Mumble
Summary
by MITRE
The needSamples method in AudioOutputSpeech.cpp in the client in Mumble 1.2.4 and the 1.2.3 pre-release snapshots, Mumble for iOS 1.1 through 1.2.2, and MumbleKit before commit fd190328a9b24d37382b269a5674b0c0c7a7e36d does not check the return value of the opus_decode_float function, which allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a crafted Opus voice packet, which triggers an error in opus_decode_float, a conversion of a negative integer to an unsigned integer, and a heap-based buffer over-read and over-write.
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Analysis
by VulDB Data Team • 02/01/2022
The vulnerability described in CVE-2014-0045 represents a critical security flaw affecting multiple versions of the Mumble voice communication software ecosystem. This vulnerability exists within the AudioOutputSpeech.cpp file in the client-side implementation of Mumble versions 1.2.4 and earlier pre-release snapshots, as well as affecting Mumble for iOS versions 1.1 through 1.2.2 and MumbleKit libraries before a specific commit. The flaw stems from inadequate error handling within the needSamples method which processes audio data received from network peers. When processing crafted Opus voice packets, the system fails to validate the return value of the opus_decode_float function, creating a dangerous condition that can be exploited by remote attackers.
The technical implementation of this vulnerability demonstrates a classic buffer over-read and over-write scenario that operates through multiple interconnected failure points. When maliciously crafted Opus packets are received, the opus_decode_float function encounters an error condition that should be properly handled. However, due to the missing return value check, the system proceeds to process this error condition as valid data. The vulnerability specifically exploits a conversion error where a negative integer value gets converted to an unsigned integer, creating an unpredictable memory access pattern. This conversion error leads to a heap-based buffer over-read and over-write condition that can corrupt adjacent memory regions and potentially overwrite critical program structures or execution control flow information.
The operational impact of this vulnerability extends beyond simple denial of service to include potential arbitrary code execution capabilities. Remote attackers can craft specific Opus voice packets that trigger the vulnerable code path, causing the affected Mumble client to crash or potentially execute malicious code with the privileges of the running process. This represents a significant threat to voice communication systems that rely on Mumble, particularly in environments where users might encounter untrusted network traffic. The vulnerability affects not just desktop clients but also mobile implementations, expanding the potential attack surface significantly. The issue demonstrates poor defensive programming practices and highlights the importance of proper input validation and error handling in multimedia processing components.
Security professionals should note that this vulnerability aligns with CWE-248, which addresses "Uncaught Exception" conditions, and also relates to CWE-125, "Out-of-Bounds Read" and CWE-787, "Out-of-Bounds Write." The attack vector follows patterns consistent with ATT&CK technique T1203, "Exploitation for Client Execution," and T1499, "Endpoint Denial of Service," as it enables both system instability and potential code execution. Organizations using Mumble should immediately implement mitigations including updating to patched versions, implementing network segmentation to limit exposure to untrusted peers, and monitoring for suspicious audio packet patterns that might indicate exploitation attempts. The vulnerability serves as a reminder of the critical importance of proper error handling in multimedia processing libraries and the potential consequences of neglecting to validate function return values in security-sensitive code paths.