CVE-2002-1081 in Abyss Web Server
Summary
by MITRE
The Administration console for Abyss Web Server 1.0.3 allows remote attackers to read files without providing login credentials via an HTTP request to a target file that ends in a "+" character.
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Analysis
by VulDB Data Team • 09/08/2025
The vulnerability identified as CVE-2002-1081 represents a critical authentication bypass flaw in the Abyss Web Server version 1.0.3 administration console. This weakness stems from improper input validation and access control mechanisms within the web server's administrative interface, allowing unauthenticated remote attackers to gain unauthorized access to sensitive files on the target system. The vulnerability specifically manifests when an attacker constructs a malicious HTTP request that targets a file path ending with a "+" character, effectively circumventing the normal authentication requirements that should be enforced before file access is granted.
The technical exploitation of this vulnerability occurs through a specific pattern in how the web server processes file requests within its administration console. When a request is made to a file path that concludes with a "+" character, the server fails to properly validate the authentication status of the requesting user. This flaw falls under the category of improper access control as defined by CWE-284, where the system does not adequately enforce authorization mechanisms. The implementation error lies in the server's inability to distinguish between legitimate authenticated requests and maliciously crafted requests that exploit this specific character sequence to bypass security checks.
The operational impact of this vulnerability is severe and multifaceted, as it provides attackers with the ability to read arbitrary files on the web server without requiring any form of authentication credentials. This could potentially expose sensitive configuration files, user data, application source code, and other confidential information stored on the server. The remote nature of the attack means that an attacker does not need physical access to the system or network, making the vulnerability particularly dangerous in environments where the web server is accessible from the internet. Attackers could leverage this vulnerability to perform reconnaissance, extract sensitive data, or potentially escalate their privileges within the system.
This vulnerability aligns with several techniques documented in the MITRE ATT&CK framework, particularly those related to credential access and privilege escalation. The attack pattern corresponds to T1110.001 - Brute Force: Password Guessing and T1566.001 - Phishing: Spearphishing Attachment, as attackers could use this vulnerability to obtain credentials or sensitive information without direct authentication attempts. The flaw also demonstrates characteristics of T1078 - Valid Accounts, where unauthorized access is achieved through legitimate authentication mechanisms that have been improperly implemented. Organizations should implement immediate mitigations including applying the vendor-provided patch, restricting access to the administration console through firewall rules, implementing network segmentation, and monitoring for suspicious file access patterns that might indicate exploitation attempts. Additionally, regular security audits and input validation reviews should be conducted to prevent similar implementation flaws in other web server components.