CVE-2002-0543 in Abyss Web Server
Summary
by MITRE
Directory traversal vulnerability in Aprelium Abyss Web Server (abyssws) before 1.0.0.2 allows remote attackers to read files outside the web root, including the abyss.conf file, via URL-encoded .. (dot dot) sequences in the HTTP request.
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Analysis
by VulDB Data Team • 09/16/2025
The CVE-2002-0543 vulnerability represents a critical directory traversal flaw in the Aprelium Abyss Web Server software, specifically affecting versions prior to 1.0.0.2. This vulnerability falls under the Common Weakness Enumeration category CWE-22, which identifies improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The flaw exists in how the web server processes URL-encoded .. (dot dot) sequences within HTTP requests, allowing malicious actors to manipulate file access paths beyond the intended web root directory. The vulnerability demonstrates a fundamental failure in input validation and path resolution mechanisms within the web server's request processing pipeline.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious HTTP request containing URL-encoded directory traversal sequences such as %2e%2e%2f or ..%2f. These sequences are designed to navigate up directory levels from the web root, potentially accessing sensitive files that should remain restricted. The attack vector specifically targets the web server's inability to properly sanitize and validate file paths before processing file access requests. When the server processes these malformed requests, it fails to implement proper path normalization or validation checks, allowing the traversal to proceed and potentially expose critical system files including configuration files like abyss.conf, which may contain sensitive information such as database credentials, user accounts, or server configuration details.
The operational impact of this vulnerability extends beyond simple unauthorized file access, representing a severe compromise of system security and data integrity. Attackers can leverage this vulnerability to access not only configuration files but potentially other sensitive system files, user data, or application source code that should remain protected within the web server's designated root directory. The exposure of the abyss.conf file specifically could reveal critical server configuration parameters, authentication mechanisms, and other sensitive information that could facilitate further attacks. This vulnerability aligns with the ATT&CK technique T1083, which describes the discovery of system information through reconnaissance activities, and T1566, which covers the use of malicious file content to gain access to systems. The vulnerability's exploitation capability provides attackers with a foundational foothold for more sophisticated attacks including privilege escalation, data exfiltration, or lateral movement within the compromised network environment.
Mitigation strategies for CVE-2002-0543 require immediate implementation of software updates to versions 1.0.0.2 or later, which contain the necessary patches to address the directory traversal vulnerability. Organizations should also implement proper input validation and sanitization measures at the web server level, ensuring that all file access requests are properly validated against a whitelist of allowed paths. Network-level protections such as web application firewalls can provide additional defense-in-depth measures by monitoring and blocking suspicious URL patterns containing directory traversal sequences. System administrators should conduct comprehensive security audits to identify and remove any vulnerable instances of the Abyss Web Server from production environments. The vulnerability also underscores the importance of implementing principle of least privilege access controls and regular security assessments to prevent similar issues in other web server implementations. Organizations should consider implementing automated vulnerability scanning tools that can detect and alert on similar path traversal patterns in web applications and services, ensuring proactive identification of potential security weaknesses before they can be exploited by malicious actors.