CVE-2010-1938 in opie
Summary
by MITRE
Off-by-one error in the __opiereadrec function in readrec.c in libopie in OPIE 2.4.1-test1 and earlier, as used on FreeBSD 6.4 through 8.1-PRERELEASE and other platforms, allows remote attackers to cause a denial of service (daemon crash) or possibly execute arbitrary code via a long username, as demonstrated by a long USER command to the FreeBSD 8.0 ftpd.
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Analysis
by VulDB Data Team • 01/25/2025
The vulnerability identified as CVE-2010-1938 represents a critical off-by-one error within the OPIE authentication library's readrec.c component, specifically in the __opiereadrec function. This flaw exists in OPIE versions 2.4.1-test1 and earlier, affecting FreeBSD systems running versions 6.4 through 8.1-PRERELEASE and other platforms that utilize this authentication library. The vulnerability stems from inadequate input validation mechanisms that fail to properly handle excessively long username inputs, creating a condition where buffer boundaries are improperly managed during authentication processes. The flaw manifests when the daemon processes a USER command with an extended username parameter, causing memory corruption that can lead to system instability.
The technical implementation of this vulnerability involves a classic buffer overflow condition where the off-by-one error allows an attacker to write beyond the allocated buffer space. When a maliciously long username is submitted through the ftpd daemon, the __opiereadrec function fails to properly terminate or validate the input string length before processing. This results in memory corruption that can cause the daemon to crash or potentially allow arbitrary code execution. The vulnerability specifically targets the authentication flow of the ftpd service, making it particularly dangerous as it can be exploited by remote attackers without requiring prior authentication credentials. The flaw operates at the boundary condition level where the buffer size calculation does not account for the null terminator, creating a single byte overflow that can be leveraged for exploitation.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to potentially enable remote code execution, making it a severe security concern for affected systems. When exploited, the vulnerability can cause the ftpd daemon to crash and restart, leading to service disruption and potential availability issues for legitimate users. However, the more concerning aspect is the possibility of arbitrary code execution, which could allow attackers to gain unauthorized access to the system and escalate privileges. This vulnerability affects systems that rely on OPIE for authentication, particularly those running FreeBSD versions within the affected range, potentially compromising the entire authentication infrastructure. The impact is particularly significant in environments where ftpd services are exposed to untrusted networks, as the vulnerability can be exploited remotely without requiring any authentication.
Mitigation strategies for CVE-2010-1938 should prioritize immediate patching of affected systems with updated OPIE versions that address the buffer overflow condition. System administrators must ensure that all FreeBSD systems within the affected version range receive the appropriate security updates from the vendor. Additionally, network segmentation and access controls should be implemented to limit exposure of ftpd services to untrusted networks, reducing the attack surface. Input validation measures should be strengthened at the application level to prevent excessively long username inputs from reaching the vulnerable function. Monitoring systems should be configured to detect unusual authentication patterns or service disruptions that might indicate exploitation attempts. The vulnerability aligns with CWE-121, which describes buffer overflow conditions, and maps to ATT&CK technique T1190 for exploitation of remote services, emphasizing the need for comprehensive defensive measures including network monitoring, intrusion detection systems, and regular security assessments to identify and remediate similar vulnerabilities in authentication frameworks.
The broader implications of this vulnerability highlight the critical importance of proper input validation and buffer management in security-critical applications. This flaw demonstrates how seemingly minor coding errors can result in significant security risks, particularly in authentication systems where attackers can leverage service exposure to gain unauthorized access. The vulnerability serves as a reminder of the necessity for thorough code review processes and the implementation of security-focused development practices that prevent such boundary condition errors from occurring in production systems. Organizations should implement robust patch management procedures to ensure timely remediation of known vulnerabilities, particularly those affecting core system components like authentication libraries that are fundamental to overall system security.