CVE-2001-0786 in Air Messenger LAN Server
Summary
by MITRE
Internet Software Solutions Air Messenger LAN Server (AMLServer) 3.4.2 stores user passwords in plaintext in the pUser.Dat file.
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Analysis
by VulDB Data Team • 04/10/2019
The vulnerability identified as CVE-2001-0786 affects the Internet Software Solutions Air Messenger LAN Server version 3.4.2, representing a critical security flaw in password storage practices that directly violates fundamental security principles. This issue stems from the application's design decision to store user credentials in plaintext format within the pUser.Dat file, creating an inherent weakness that exposes sensitive authentication data to unauthorized access. The flaw demonstrates poor security implementation where the system fails to apply proper cryptographic measures to protect user passwords, leaving them vulnerable to disclosure when the file is accessed by unauthorized parties. This vulnerability directly relates to CWE-256, which addresses the storage of cleartext passwords, and represents a clear violation of the principle of least privilege in information security.
The technical implementation of this vulnerability occurs at the application level where user authentication data is persisted without any form of encryption or hashing mechanisms. When users create accounts or modify their credentials within the AMLServer environment, the system writes these passwords directly to the pUser.Dat file in readable format rather than employing secure password storage practices such as salted hashing or encryption. This plaintext storage approach means that any individual with access to the file system where the pUser.Dat file resides can immediately read and utilize the stored passwords for unauthorized authentication attempts. The vulnerability is particularly concerning because it eliminates the need for sophisticated attack vectors, as the passwords are readily available in the clear, making this a high-impact flaw from both exploitation and impact perspectives.
The operational impact of this vulnerability extends beyond simple credential theft to encompass broader security implications for organizations relying on the AMLServer for communication services. System administrators and attackers with file system access can immediately compromise multiple user accounts by simply reading the pUser.Dat file, potentially leading to complete system takeover and unauthorized access to sensitive communication channels. This flaw creates a persistent risk that remains active until the underlying application is patched or the vulnerable configuration is corrected, as the plaintext passwords can be used for lateral movement within the network. The vulnerability also affects the organization's overall security posture by demonstrating inadequate security controls and potentially violating compliance requirements such as those outlined in the Payment Card Industry Data Security Standard, which mandates secure storage of authentication credentials.
The attack surface for this vulnerability is significantly expanded due to the nature of the plaintext storage approach, as it requires only local file system access to exploit the flaw. This makes the vulnerability particularly dangerous in environments where multiple users have access to the server or where file system permissions are not properly enforced. The vulnerability aligns with ATT&CK technique T1566, which covers credential harvesting through file system access, and represents a classic example of how insecure data storage can undermine even the most sophisticated network security measures. Organizations should implement immediate mitigations including restricting file system access to the pUser.Dat file, applying proper access controls, and migrating to secure password storage mechanisms. Additionally, the vulnerability highlights the importance of following security best practices such as those outlined in the OWASP Top Ten, specifically addressing the storage of sensitive data and the implementation of proper authentication mechanisms to prevent similar issues in future deployments.