CVE-2002-0800 in BadBlue
Summary
by MITRE
BadBlue 1.7.0 allows remote attackers to list the contents of directories via a URL with an encoded % character at the end.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 09/13/2025
The vulnerability identified as CVE-2002-0800 affects BadBlue web server version 1.7.0, representing a directory traversal security flaw that enables remote attackers to enumerate directory contents through specifically crafted URL requests. This issue stems from improper handling of URL encoding sequences, particularly when the % character is appended to directory paths in web requests. The vulnerability resides in the web server's request parsing mechanism where encoded characters are not properly sanitized or validated before being processed, allowing malicious actors to bypass normal access controls and gain unauthorized visibility into server file structures.
The technical implementation of this flaw involves the web server's failure to properly decode and validate URL-encoded sequences, specifically when the % character appears at the end of directory paths in HTTP requests. When a remote attacker submits a URL containing an encoded % character at the termination point, the BadBlue server fails to properly interpret this sequence, resulting in the server returning directory listing information instead of properly handling the request. This behavior creates an information disclosure vulnerability where attackers can discover the presence of files and directories that would normally be protected from public access. The vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, and represents a classic case of insufficient input validation in web applications. The flaw operates at the application layer of the network stack, making it particularly dangerous as it can be exploited through standard HTTP protocols without requiring specialized tools or deep system knowledge.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with valuable reconnaissance data that can be used to plan further attacks. Directory listings reveal the presence of sensitive files, backup copies, configuration files, and potentially vulnerable application components that could be targeted in subsequent exploitation phases. This information disclosure vulnerability can be leveraged as a stepping stone for more sophisticated attacks, including potential exploitation of other vulnerabilities present in the server environment. The attack vector is particularly concerning because it requires minimal technical expertise to execute, making it attractive to both novice and experienced attackers. According to ATT&CK framework, this vulnerability maps to T1083 (File and Directory Discovery) and T1592 (Gather Victim Host Information) techniques, demonstrating how simple path traversal flaws can enable broader reconnaissance activities.
Mitigation strategies for CVE-2002-0800 should focus on immediate server updates and configuration hardening measures. The most effective solution involves upgrading to a patched version of BadBlue web server that properly handles URL encoding sequences and implements proper input validation for all incoming requests. Organizations should implement comprehensive URL validation mechanisms that reject or properly sanitize any requests containing suspicious encoded sequences. Network administrators should configure web server security policies to disable directory listing features and implement proper access controls that prevent unauthorized enumeration of file systems. Additionally, implementing web application firewalls and intrusion detection systems can help identify and block malicious requests attempting to exploit this vulnerability. Regular security assessments and vulnerability scanning should be conducted to identify similar flaws in other web applications and services within the network infrastructure. The remediation process should include thorough testing to ensure that legitimate functionality remains intact while addressing the security weakness.