CVE-2005-2850 in SlimFTPd
Summary
by MITRE
SlimFTPd 3.17 allows remote attackers to cause a denial of service (crash) via certain (1) USER and (2) PASS commands, possibly due to a buffer overflow or off-by-one error.
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Analysis
by VulDB Data Team • 06/29/2025
The vulnerability identified as CVE-2005-2850 affects SlimFTPd version 3.17 and represents a critical denial of service flaw that can be exploited by remote attackers to crash the FTP server. This vulnerability manifests when specific USER and PASS commands are sent to the server, indicating a potential buffer overflow condition or off-by-one error in the command processing logic. The attack vector is particularly concerning as it allows remote exploitation without requiring authentication, making it accessible to any attacker with network access to the affected server.
The technical implementation of this vulnerability stems from inadequate input validation and memory management within the SlimFTPd server's authentication handling mechanism. When the server processes USER and PASS commands, it appears to fail to properly bounds-check the incoming data, leading to memory corruption that ultimately results in a crash. This type of vulnerability falls under the CWE-121 category of stack-based buffer overflow, though the specific implementation may involve heap corruption or other memory management issues. The flaw represents a classic example of unsafe string handling where the server does not adequately validate the length or content of authentication credentials before processing them.
From an operational perspective, this vulnerability creates significant risk for organizations relying on SlimFTPd for file transfer services. The denial of service condition effectively renders the FTP server unavailable to legitimate users, disrupting business operations and potentially impacting critical file transfer workflows. Attackers can exploit this vulnerability with minimal technical skill, requiring only basic network connectivity and knowledge of FTP command sequences. The impact extends beyond simple service disruption as it can be used as part of larger attack campaigns to disable critical infrastructure components. This vulnerability aligns with ATT&CK technique T1499.004 for network denial of service attacks, where adversaries target network infrastructure to prevent access to services.
The mitigation strategy for this vulnerability requires immediate patching of the SlimFTPd server to version 3.18 or later, which contains the necessary fixes for the buffer overflow conditions. Organizations should also implement network segmentation to limit exposure of FTP services to untrusted networks and consider deploying intrusion detection systems to monitor for suspicious FTP command sequences. Additionally, administrators should conduct thorough vulnerability assessments of all FTP server implementations within their environment to identify similar issues in other software components. The fix typically involves implementing proper input validation, bounds checking, and memory management practices that prevent the exploitation of buffer overflow conditions. Regular security updates and patch management procedures should be enforced to prevent similar vulnerabilities from emerging in other network services and applications.