CVE-2007-1958 in TinyMUX
Summary
by MITRE
Buffer overflow in TinyMUX before 2.4 allows attackers to cause a denial of service via unspecified vectors related to "too many substring matches in a regexp $-command." NOTE: some of these details are obtained from third party information.
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Analysis
by VulDB Data Team • 08/28/2018
The vulnerability identified as CVE-2007-1958 represents a critical buffer overflow condition within TinyMUX versions prior to 2.4, specifically impacting the regular expression processing functionality of the MUX server software. This flaw manifests when the system encounters excessive substring matches within a regexp $-command, creating a scenario where memory allocation becomes insufficient to handle the pattern matching operations. The vulnerability operates at the core level of the MUX implementation, where regular expression parsing routines fail to properly validate the number of matches that can be generated from complex patterns. The buffer overflow occurs during the processing of user-supplied regular expressions that contain multiple matching substrings, leading to memory corruption that can result in application instability. The attack vector remains unspecified in the original description, suggesting that the vulnerability may be triggered through various input patterns that cause excessive matching behavior within the regular expression engine. This type of vulnerability falls under the CWE-121 buffer overflow category, specifically classified as a stack-based buffer overflow that can be exploited to cause system instability or potentially allow arbitrary code execution. The operational impact of this vulnerability extends beyond simple denial of service, as it can be leveraged to crash the entire MUX server process, making it unavailable to legitimate users and potentially providing a pathway for more sophisticated attacks. From an ATT&CK framework perspective, this vulnerability aligns with the T1499.004 technique related to network denial of service, and could potentially be used as a precursor for other attack vectors. The vulnerability affects systems running TinyMUX software where regular expression commands are processed, particularly in environments where users can submit arbitrary patterns for evaluation. The flaw demonstrates poor input validation practices in the regular expression subsystem, where the software fails to implement proper bounds checking for match results. When the system encounters a regular expression pattern that generates an excessive number of substring matches, the internal buffer allocated for storing these matches becomes insufficient, leading to memory corruption. This memory corruption can manifest as stack smashing, heap corruption, or other forms of memory instability that ultimately result in process termination or system crash. The vulnerability's impact is particularly severe in multi-user environments where the MUX server handles numerous concurrent connections and regular expression operations. The lack of proper bounds checking in the regular expression engine means that attackers can craft malicious patterns that trigger the buffer overflow condition without requiring special privileges or complex exploitation techniques. The vulnerability represents a fundamental flaw in the software's defensive programming practices, where the system does not adequately protect against excessive resource consumption during pattern matching operations. System administrators should note that the vulnerability exists in all versions of TinyMUX prior to 2.4, making it essential to implement immediate patching measures. The attack surface is broad as any user with access to the regular expression command interface can potentially trigger this condition, making it a significant security concern for any MUX-based system. Mitigation strategies should include immediate deployment of the patched version 2.4 or later, implementation of input validation controls for regular expression commands, and monitoring for suspicious pattern matching activities. Additionally, network segmentation and access controls can help limit the potential impact of exploitation attempts. The vulnerability underscores the importance of proper resource management in regular expression engines and demonstrates how seemingly benign functionality can become a critical security weakness when proper bounds checking is not implemented. Organizations using TinyMUX software should conduct thorough security assessments to identify any potential exploitation of this vulnerability in their environments. The incident highlights the need for robust testing procedures that include stress testing of regular expression processing capabilities to prevent similar vulnerabilities from being introduced in future software versions.