CVE-2006-5981 in SeleniumServer FTP Server
Summary
by MITRE
Multiple directory traversal vulnerabilities in SeleniumServer FTP Server 1.0, and possibly earlier, allow remote attackers to list arbitrary directories, read arbitrary files, and upload arbitrary files via directory traversal sequences in the (1) DIR (LIST or NLST), (2) GET (RETR), and (3) PUT (STOR) commands.
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Analysis
by VulDB Data Team • 04/28/2026
The vulnerability identified as CVE-2006-5981 represents a critical directory traversal flaw in the SeleniumServer FTP Server version 1.0 and potentially earlier releases. This security weakness stems from insufficient input validation and improper path handling within the FTP server implementation, creating opportunities for remote attackers to exploit multiple command interfaces including DIR, GET, and PUT operations. The vulnerability operates at the core of file system access controls, allowing unauthorized entities to bypass normal access restrictions and gain elevated privileges within the server's file system hierarchy.
The technical exploitation of this vulnerability occurs through carefully crafted directory traversal sequences that manipulate the FTP server's interpretation of file paths. When attackers issue DIR commands using LIST or NLST operations, they can traverse beyond the intended directory boundaries to access arbitrary directories on the server. Similarly, GET commands with RETR functionality can retrieve files from locations outside the designated file access scope, while PUT commands using STOR can upload malicious content to arbitrary locations within the file system. This three-pronged attack vector demonstrates the comprehensive nature of the flaw, affecting both read and write operations within the FTP server's architecture.
The operational impact of CVE-2006-5981 extends beyond simple unauthorized access to encompass complete system compromise potential. Attackers can leverage this vulnerability to enumerate directory structures, exfiltrate sensitive data, and potentially establish persistent access through file uploads. The vulnerability directly violates fundamental security principles of least privilege and proper input sanitization, creating a pathway for attackers to move laterally within networks where the FTP server operates. This type of vulnerability aligns with CWE-22 Directory Traversal and represents a classic example of how insufficient input validation can lead to complete system compromise.
From a cybersecurity perspective, this vulnerability demonstrates the importance of implementing proper path validation and access control mechanisms in network services. The attack vectors align with techniques described in the MITRE ATT&CK framework under the T1078 and T1566 tactics, where adversaries gain access to systems through legitimate credentials and establish persistence. Organizations running affected versions of SeleniumServer FTP Server face significant risk of data breaches, system compromise, and potential regulatory violations. The vulnerability also highlights the need for comprehensive security testing of network services, particularly those handling file operations, to identify and remediate similar weaknesses before they can be exploited by malicious actors.
The remediation approach for CVE-2006-5981 requires immediate patching of the SeleniumServer FTP Server to address the directory traversal flaws. Organizations should implement proper input validation and path sanitization measures to prevent traversal sequences from being processed as legitimate file operations. Network segmentation and access controls should be enforced to limit exposure of FTP services to trusted networks only. Additionally, regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other network services and applications. The vulnerability serves as a reminder of the critical importance of maintaining up-to-date security patches and implementing robust input validation mechanisms across all network-facing services to prevent unauthorized access and data compromise.