CVE-2017-18189 in Sound eXchange
Summary
by MITRE
In the startread function in xa.c in Sound eXchange (SoX) through 14.4.2, a corrupt header specifying zero channels triggers an infinite loop with a resultant NULL pointer dereference, which may allow a remote attacker to cause a denial-of-service.
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Analysis
by VulDB Data Team • 02/08/2023
The vulnerability identified as CVE-2017-18189 resides within the Sound eXchange (SoX) multimedia processing library version 14.4.2 and earlier, specifically within the startread function located in the xa.c file. This flaw represents a critical denial-of-service condition that can be exploited remotely through manipulation of audio file headers. The issue manifests when a malformed audio file header contains a specification of zero channels, which triggers an abnormal execution path in the software's parsing logic.
The technical root cause of this vulnerability stems from inadequate input validation within the startread function, which fails to properly handle edge cases involving channel count specifications. When SoX encounters a header with zero channels, the parsing logic enters an infinite loop where the program continuously iterates through a processing loop without proper termination conditions. This infinite loop eventually leads to a NULL pointer dereference as the software attempts to access memory locations that have not been properly initialized or allocated. The vulnerability is classified as a CWE-835: Loop with Unreachable Exit Condition, which directly relates to improper loop control structures that can lead to resource exhaustion and system instability.
The operational impact of this vulnerability extends beyond simple service disruption, as it provides a remote attacker with a reliable method to cause system instability in applications that utilize SoX for audio processing. The infinite loop consumes CPU resources continuously while the NULL pointer dereference can potentially crash the application or cause it to become unresponsive, effectively rendering the service unavailable to legitimate users. This type of vulnerability falls under ATT&CK technique T1499.004: Endpoint Denial of Service, where adversaries specifically target application-level vulnerabilities to disrupt service availability.
Mitigation strategies for this vulnerability require immediate patching of affected SoX installations to version 14.4.3 or later, which contains the necessary fixes for proper header validation and loop termination conditions. Organizations should also implement input validation measures at the application level to filter out malformed audio files before they reach the SoX processing pipeline. Additionally, network-level filtering can be employed to block suspicious file types or malformed headers, though this approach provides only partial protection. The fix implemented by the SoX development team addresses the core issue by introducing proper bounds checking and early termination conditions for channel count validation, preventing the infinite loop scenario that previously led to resource exhaustion and system instability.