CVE-1999-0474 in ICQ
Summary
by MITRE
The ICQ Webserver allows remote attackers to use .. to access arbitrary files outside of the user's personal directory.
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Analysis
by VulDB Data Team • 04/19/2026
The vulnerability described in CVE-1999-0474 represents a classic directory traversal flaw that affected the ICQ webserver implementation. This security weakness stems from inadequate input validation within the web server's file access mechanisms, allowing malicious actors to exploit path traversal sequences using the double dot notation. The vulnerability specifically impacts the ICQ webserver's ability to properly sanitize user-supplied file paths, creating a pathway for unauthorized access to system files beyond the intended user directory boundaries. This type of vulnerability falls under the category of improper input validation as defined by CWE-22, which specifically addresses path traversal attacks that occur when applications fail to properly validate or sanitize user input that is used to construct file paths.
The technical exploitation of this vulnerability occurs when a remote attacker crafts malicious HTTP requests containing directory traversal sequences such as "../" or "..\" to navigate outside of the designated web root or user personal directory. The ICQ webserver, lacking proper path validation mechanisms, processes these sequences directly without implementing adequate restrictions or sanitization routines. This allows attackers to access sensitive files including configuration data, user credentials, system logs, and potentially system binaries that should remain protected within the server's restricted file access environment. The vulnerability is particularly dangerous because it can be exploited without requiring authentication, making it a critical security risk for any system running the vulnerable ICQ webserver component.
The operational impact of this vulnerability extends beyond simple unauthorized file access, as it can lead to complete system compromise when combined with other attack vectors. An attacker who successfully exploits this vulnerability can potentially obtain sensitive information such as user account details, system configuration files, and application data that may contain passwords or other authentication tokens. The vulnerability also enables further attack progression by allowing access to system resources that could be used to escalate privileges or establish persistent access. According to ATT&CK framework, this vulnerability maps to T1083 (File and Directory Discovery) and T1566 (Phishing with Social Engineering) as attackers can use the discovered information to craft more sophisticated attacks. The exposure of system files and configurations can also facilitate additional reconnaissance activities that may lead to more severe compromise of the affected system.
Mitigation strategies for this vulnerability require immediate implementation of proper input validation and path sanitization mechanisms within the ICQ webserver. Organizations should implement strict file path validation that rejects or removes directory traversal sequences from user-supplied input before processing file access requests. The web server should be configured with proper access controls that enforce strict boundaries on file system access, ensuring that all file operations occur within designated safe directories. Additionally, system administrators should consider implementing web application firewalls or intrusion prevention systems that can detect and block known directory traversal attack patterns. Regular security updates and patches should be applied to the ICQ webserver software, and in cases where the webserver functionality is not essential, it should be disabled or removed from production environments. The vulnerability also underscores the importance of following secure coding practices and implementing proper input validation as outlined in the OWASP Top Ten security controls, which specifically addresses path traversal attacks as a critical security concern that requires immediate attention and remediation.