CVE-2002-0844 in CVSD
Summary
by MITRE
Off-by-one overflow in the CVS PreservePermissions of rcs.c for CVSD before 1.11.2 allows local users to execute arbitrary code.
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Analysis
by VulDB Data Team • 09/05/2019
The vulnerability identified as CVE-2002-0844 represents a critical off-by-one buffer overflow condition within the Concurrent Versions System (CVS) software suite, specifically affecting the rcs.c file's PreservePermissions functionality. This flaw exists in CVSD versions prior to 1.11.2 and creates a dangerous condition where local attackers can manipulate memory boundaries to execute arbitrary code with elevated privileges. The vulnerability stems from improper bounds checking during the processing of file permissions within the revision control system, creating a pathway for privilege escalation attacks. The issue manifests when the system attempts to preserve file permissions during version control operations, where a single byte error in memory allocation allows attackers to overwrite adjacent memory locations.
The technical exploitation of this vulnerability follows a classic buffer overflow pattern where an attacker can manipulate input data to exceed allocated memory boundaries by precisely one byte. This off-by-one error in the rcs.c file's PreservePermissions function creates a condition where the system allocates memory for permission data but fails to account for proper boundary validation. When processing file permissions during CVS operations, the software incorrectly calculates memory boundaries, allowing an attacker to inject malicious code into adjacent memory segments. The vulnerability is particularly dangerous because it operates within the context of the CVSD daemon, which typically runs with elevated privileges, making successful exploitation potentially catastrophic for system security. This type of vulnerability aligns with CWE-121, which categorizes heap-based buffer overflow conditions, and represents a fundamental flaw in memory management practices.
The operational impact of CVE-2002-0844 extends beyond simple code execution, as it enables attackers to gain unauthorized access to systems running vulnerable CVS implementations. Local users who can interact with the CVSD service can leverage this vulnerability to escalate their privileges and potentially compromise entire network infrastructures. The exploitability of this condition is enhanced by the fact that CVSD typically operates with elevated permissions, meaning that successful exploitation could provide attackers with root-level access to affected systems. The vulnerability affects organizations that rely on CVS for version control management, particularly those with poorly configured security policies or systems where local users have access to the version control environment. Attackers can utilize this flaw to install backdoors, modify critical system files, or establish persistent access points within the network infrastructure. The vulnerability also creates opportunities for lateral movement within networks where CVS servers are used as central points for code management and version control.
Mitigation strategies for CVE-2002-0844 focus primarily on immediate software updates and system hardening measures. Organizations should prioritize upgrading to CVSD version 1.11.2 or later, which contains the necessary patches to address the off-by-one overflow condition in the rcs.c file. Additionally, system administrators should implement strict access controls to limit local user privileges and monitor CVSD daemon operations for suspicious activities. Network segmentation and firewall rules can help prevent unauthorized access to CVS servers, while regular security audits should verify that no unauthorized modifications have occurred. The implementation of intrusion detection systems can help identify potential exploitation attempts, and organizations should consider deploying additional monitoring tools to track file permission changes and system calls related to the vulnerable functionality. Security professionals should also review and update their incident response procedures to ensure preparedness for potential exploitation of this vulnerability, particularly in environments where legacy CVS systems remain operational. The vulnerability demonstrates the importance of thorough memory management practices and proper bounds checking in security-critical applications, aligning with ATT&CK technique T1068 which covers privilege escalation through local exploitation of system vulnerabilities.