CVE-2001-0550 in wu-ftpd
Summary
by MITRE
wu-ftpd 2.6.1 allows remote attackers to execute arbitrary commands via a "~{" argument to commands such as CWD, which is not properly handled by the glob function (ftpglob).
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Analysis
by VulDB Data Team • 10/05/2025
The vulnerability identified as CVE-2001-0550 represents a critical command injection flaw in wu-ftpd version 2.6.1 that enables remote attackers to execute arbitrary commands on affected systems. This vulnerability specifically targets the globbing functionality within the ftpglob function, which fails to properly sanitize input arguments containing the "~{" pattern. The issue arises when users submit commands such as CWD with maliciously crafted arguments that exploit the improper handling of glob patterns, creating a pathway for unauthorized command execution.
The technical flaw stems from inadequate input validation and sanitization within the ftpglob function that processes file system operations. When the CWD command receives an argument containing the "~{" pattern, the function does not properly escape or filter this input before processing it through the globbing mechanism. This allows attackers to inject shell commands that get executed with the privileges of the ftp daemon process, potentially leading to complete system compromise. The vulnerability operates at the intersection of improper input validation and shell command execution, making it particularly dangerous for network services.
The operational impact of this vulnerability extends beyond simple command execution to encompass full system compromise when exploited successfully. Attackers can leverage this flaw to gain unauthorized access to the affected system, potentially escalating privileges and establishing persistent access. The remote nature of the attack means that exploitation does not require local system access, making it particularly attractive to threat actors who seek to compromise systems without physical presence. This vulnerability directly maps to CWE-78, which describes improper neutralization of special elements used in OS commands, and aligns with ATT&CK technique T1059.001 for command and script injection.
Mitigation strategies for this vulnerability include immediate patching of the wu-ftpd software to version 2.6.2 or later, which contains the necessary fixes for the globbing function. System administrators should also implement network segmentation and firewall rules to restrict access to ftp services, particularly from untrusted networks. Additional defensive measures include disabling unnecessary ftp services, implementing strong authentication mechanisms, and monitoring for suspicious ftp activity patterns. Organizations should conduct vulnerability assessments to identify all systems running affected versions of wu-ftpd and ensure comprehensive patch management procedures are in place to prevent similar issues from occurring in the future.