CVE-2007-5300 in wzdftpd
Summary
by MITRE
Off-by-one error in the do_login_loop function in libwzd-core/wzd_login.c in wzdftpd 0.8.0, 0.8.2, and possibly other versions allows remote attackers to cause a denial of service (daemon crash) via a long USER command that triggers a stack-based buffer overflow. NOTE: some of these details are obtained from third party information.
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Analysis
by VulDB Data Team • 10/07/2024
The vulnerability identified as CVE-2007-5300 represents a critical stack-based buffer overflow flaw within the wzdftpd FTP daemon software. This issue manifests in the do_login_loop function located within the libwzd-core/wzd_login.c source file, affecting versions 0.8.0 and 0.8.2 of the software. The flaw stems from an off-by-one error that occurs when processing USER commands, where the software fails to properly validate input length before copying data to a fixed-size stack buffer. This type of vulnerability falls under CWE-121 Stack-based Buffer Overflow, which is classified as a fundamental memory safety issue that can lead to arbitrary code execution or system instability. The vulnerability operates at the application layer within the FTP protocol implementation, specifically targeting the authentication phase of the daemon's operation.
The operational impact of this vulnerability extends beyond simple denial of service, as it creates a potential attack surface for remote exploitation. When a remote attacker sends a specially crafted USER command containing excessive data, the off-by-one error causes the buffer to overflow, corrupting adjacent stack memory and ultimately leading to daemon crash. This behavior aligns with the ATT&CK technique T1499.004 for Network Denial of Service, where attackers can disrupt services by exploiting software vulnerabilities. The stack-based nature of the overflow means that the attacker can potentially overwrite return addresses, function pointers, or other critical stack variables, though the current description indicates the primary effect is daemon crash rather than arbitrary code execution. The vulnerability affects the core authentication functionality of the FTP daemon, making it a particularly dangerous issue for systems relying on this service for file transfer operations.
Mitigation strategies for CVE-2007-5300 should prioritize immediate software updates to patched versions of wzdftpd, as the vulnerability has existed for over a decade and likely has well-documented fixes available in updated releases. Organizations should implement network segmentation to limit exposure of FTP services to trusted networks only, while also deploying intrusion detection systems capable of identifying suspicious USER command patterns. Input validation measures should be strengthened at the application level, including implementing strict bounds checking for all user input before processing. The vulnerability's classification as a stack-based buffer overflow makes it particularly susceptible to exploitation techniques such as stack smashing protection bypasses, though the primary concern remains the denial of service impact. Security monitoring should focus on anomalous FTP authentication attempts and unusual USER command lengths that could indicate exploitation attempts. Additionally, implementing proper error handling and graceful degradation mechanisms within the FTP daemon can help prevent complete service outages even if exploitation occurs, while maintaining compliance with security standards such as NIST SP 800-125 for secure software development practices.