CVE-2013-4256 in Network Audio System
Summary
by MITRE
Multiple stack-based and heap-based buffer overflows in Network Audio System (NAS) 1.9.3 allow local users to cause a denial of service (crash) or possibly execute arbitrary code via the (1) display command argument to the ProcessCommandLine function in server/os/utils.c; (2) ResetHosts function in server/os/access.c; (3) open_unix_socket, (4) open_isc_local, (5) open_xsight_local, (6) open_att_local, or (7) open_att_svr4_local function in server/os/connection.c; the (8) AUDIOHOST environment variable to the CreateWellKnownSockets or (9) AmoebaTCPConnectorThread function in server/os/connection.c; or (10) unspecified vectors related to logging in the osLogMsg function in server/os/aulog.c.
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Analysis
by VulDB Data Team • 01/08/2022
The vulnerability described in CVE-2013-4256 represents a critical security flaw in the Network Audio System version 1.9.3 that exposes multiple buffer overflow conditions across several core components of the audio server implementation. These vulnerabilities arise from insufficient input validation and improper memory management practices within the NAS server software, creating opportunities for malicious local users to exploit these weaknesses for either denial of service or arbitrary code execution. The affected functions span across multiple source files including server/os/utils.c, server/os/access.c, and server/os/connection.c, demonstrating a systemic issue in the software's approach to handling user inputs and system resources. The presence of both stack-based and heap-based buffer overflows indicates that the vulnerability exploitation can occur through different memory allocation patterns, making the attack surface more extensive and potentially more difficult to defend against.
The technical exploitation of these buffer overflows occurs through specific command line arguments and environment variable manipulations that bypass normal input validation mechanisms. The ProcessCommandLine function in utils.c accepts display command arguments that are not properly bounds-checked, allowing attackers to overflow the allocated stack space and potentially overwrite critical program execution data. Similarly, the ResetHosts function in access.c demonstrates a heap-based overflow condition when processing host information, which can corrupt heap metadata and lead to unpredictable program behavior. The socket opening functions including open_unix_socket, open_isc_local, and others in connection.c present additional vectors where insufficient buffer handling allows attackers to overwrite memory structures during network connection establishment. The AUDIOHOST environment variable processing through CreateWellKnownSockets and AmoebaTCPConnectorThread functions creates another pathway for exploitation, as environment variables are often not subjected to the same rigorous validation as command line arguments. The osLogMsg function in aulog.c contains unspecified logging-related vulnerabilities that can be triggered through various input patterns, indicating that the logging subsystem also suffers from inadequate memory management practices.
The operational impact of CVE-2013-4256 extends beyond simple system crashes, as local users with access to the affected system can potentially achieve arbitrary code execution with the privileges of the NAS service account. This represents a significant escalation from simple denial of service conditions, as successful exploitation could allow attackers to gain persistent access to the system or escalate privileges further. The vulnerability affects the core audio server functionality, which may be running with elevated privileges, making the potential impact more severe. The attack vectors are particularly concerning because they involve common system interaction points such as command line processing, environment variable handling, and network connection establishment, which are frequently used by legitimate system operations. The combination of multiple exploitation points increases the probability of successful attack and provides attackers with multiple pathways to achieve their objectives.
Mitigation strategies for CVE-2013-4256 should focus on comprehensive input validation and memory management improvements across all affected functions. The primary recommendation involves implementing proper bounds checking for all input parameters, particularly those derived from command line arguments and environment variables. Developers should employ modern memory-safe programming practices including the use of safe string handling functions and proper buffer size management. The affected functions should be reviewed and updated to prevent stack and heap overflows through explicit size validation and memory allocation checks. System administrators should consider implementing access controls to limit local user privileges and reduce the attack surface. Additionally, regular security updates and patches should be applied to ensure that the NAS server operates with the latest security mitigations. The vulnerability aligns with CWE-121 stack-based buffer overflow and CWE-122 heap-based buffer overflow categories, and represents a clear violation of ATT&CK technique T1059 for command and scripting interpreter usage, as exploitation typically involves manipulating command line arguments and environment variables to achieve system compromise. Organizations should also implement monitoring for unusual system behavior that might indicate exploitation attempts, particularly around audio server processes and related network connections.