CVE-2005-0373 in Linux
Summary
by MITRE
Buffer overflow in digestmd5.c CVS release 1.170 (also referred to as digestmda5.c), as used in the DIGEST-MD5 SASL plugin for Cyrus-SASL but not in any official releases, allows remote attackers to execute arbitrary code.
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Analysis
by VulDB Data Team • 05/30/2019
The vulnerability identified as CVE-2005-0373 represents a critical buffer overflow flaw within the digestmd5.c component of the Cyrus-SASL implementation. This specific version of the DIGEST-MD5 SASL plugin, which was present in CVS release 1.170 but never included in official distributions, demonstrates a classic security weakness that could be exploited by remote attackers to gain unauthorized code execution privileges. The vulnerability resides in the handling of authentication data within the Simple Authentication and Security Layer framework, which is fundamental to secure network communications.
The technical implementation flaw occurs when the digestmd5.c module processes incoming authentication requests without proper bounds checking on user-supplied data. This allows an attacker to craft malicious input that exceeds the allocated buffer space, causing memory corruption that can be leveraged to overwrite critical program execution flow. The vulnerability specifically targets the DIGEST-MD5 authentication mechanism that is commonly used in email servers, LDAP services, and other network applications that rely on SASL for secure authentication. According to CWE classification, this represents a CWE-121: Stack-based Buffer Overflow, which is categorized under the broader weakness of improper input validation.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with the ability to compromise entire systems that rely on vulnerable Cyrus-SASL implementations. Since the DIGEST-MD5 SASL plugin is frequently used in email infrastructure including postfix, sendmail, and various LDAP implementations, exploitation could lead to unauthorized access to email servers, directory services, and potentially escalate privileges within the affected systems. The vulnerability's remote exploitability means that attackers do not require local access or credentials to initiate the attack, making it particularly dangerous in networked environments where authentication services are exposed to external traffic. This aligns with ATT&CK technique T1210: Exploitation of Remote Services, which involves leveraging vulnerabilities in network services to gain unauthorized access.
Mitigation strategies for this vulnerability primarily focus on immediate remediation through software updates and patches. Organizations should ensure they are running official releases of Cyrus-SASL that do not contain the vulnerable digestmd5.c code, as the affected CVS version was never officially released. System administrators should implement network segmentation to limit exposure of authentication services to trusted networks only, and consider disabling unnecessary authentication mechanisms when not required. Additional protective measures include implementing intrusion detection systems to monitor for suspicious authentication patterns and conducting regular security assessments of authentication infrastructure. The vulnerability also highlights the importance of proper code review processes and the need to avoid deploying code from development repositories directly into production environments, as the affected code was present in CVS but never made it into stable releases.