CVE-2002-1209 in TFTP Server
Summary
by MITRE
Directory traversal vulnerability in SolarWinds TFTP Server 5.0.55, and possibly earlier, allows remote attackers to read arbitrary files via "..\" (dot-dot backslash) sequences in a GET request.
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Analysis
by VulDB Data Team • 07/07/2025
The directory traversal vulnerability identified in CVE-2002-1209 affects SolarWinds TFTP Server version 5.0.55 and potentially earlier releases, representing a critical security flaw that enables remote attackers to access files outside the intended directory structure. This vulnerability specifically manifests when the server processes GET requests containing "..\" sequences, which are standard directory navigation patterns used to move up directory levels in file systems. The flaw exists in the server's handling of file path resolution, where input validation fails to properly sanitize or restrict directory traversal sequences, allowing malicious actors to bypass normal access controls and retrieve sensitive files from the system.
The technical implementation of this vulnerability stems from inadequate input sanitization within the TFTP server's file access routines. When a client sends a GET request with a filename containing "..\" sequences, the server fails to properly validate or normalize the path before attempting to access the file. This allows an attacker to construct malicious requests that traverse upward through the directory hierarchy, potentially accessing system files, configuration data, or other sensitive information that should remain protected. The vulnerability operates at the application layer and can be exploited without requiring authentication, making it particularly dangerous for networked environments where the TFTP server is accessible to untrusted users.
From an operational impact perspective, this vulnerability creates significant risks for organizations using SolarWinds TFTP Server in their infrastructure. Attackers can leverage this flaw to access critical system files, configuration parameters, and potentially sensitive data stored on the server. The vulnerability is particularly concerning because TFTP servers are often used for network booting, firmware updates, and other critical network operations, making them attractive targets for attackers seeking to compromise network infrastructure. The remote nature of the exploit means that attackers can potentially access these files from anywhere on the network, without requiring physical access or local system credentials. This vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks.
The exploitation of this vulnerability follows established patterns documented in various threat frameworks including the MITRE ATT&CK framework, specifically relating to techniques involving privilege escalation and credential access through file system manipulation. The attack vector represents a classic example of how insufficient input validation can lead to severe security consequences, particularly in network services that handle file access operations. Organizations may find that the vulnerability allows attackers to read system configuration files, log data, or other sensitive information that could be used for further exploitation or to gain deeper insights into the target environment. The impact extends beyond simple file access, as the information retrieved could potentially reveal network topology, system configurations, or other intelligence useful for advanced persistent threats.
Mitigation strategies for this vulnerability should include immediate patching of the SolarWinds TFTP Server to the latest available version that addresses this specific directory traversal flaw. Organizations should also implement network segmentation to limit access to the TFTP server to only trusted hosts, disable unnecessary TFTP services, and monitor network traffic for suspicious GET requests containing directory traversal sequences. Additionally, implementing proper input validation at the application level, including strict path normalization and validation of file access requests, can prevent similar vulnerabilities from occurring in other services. Network administrators should also consider implementing intrusion detection systems that can identify and alert on suspicious TFTP traffic patterns that may indicate exploitation attempts. The vulnerability serves as a reminder of the importance of input validation and proper access control mechanisms in network services, particularly those handling file system operations.