CVE-1999-0397 in NT Password Appraiser
Summary
by MITRE
The demo version of the Quakenbush NT Password Appraiser sends passwords across the network in plaintext.
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Analysis
by VulDB Data Team • 04/17/2026
The vulnerability described in CVE-1999-0397 represents a critical security flaw in the Quakenbush NT Password Appraiser demo software released in the late 1990s. This issue specifically affects the demo version of the application designed to assess password security on windows nt systems. The vulnerability stems from the application's improper handling of authentication credentials during network communication, creating an exploitable vector for attackers to intercept sensitive information. The flaw is particularly concerning because it occurs in a tool ostensibly designed for security assessment, yet inadvertently creates security risks during its own operation. This demonstrates the importance of secure coding practices even in demonstration or testing software that may be deployed in production environments. The vulnerability aligns with CWE-312 which addresses the exposure of sensitive information through improper handling of data, and represents a clear violation of the principle of least privilege in network communications.
The technical implementation of this vulnerability involves the application's network protocol handling where passwords are transmitted without any form of encryption or obfuscation. When the demo version of Quakenbush NT Password Appraiser establishes network connections to assess password strength, it sends authentication credentials in plaintext format across the network infrastructure. This means that any network monitoring tools or packet sniffers positioned along the communication path can easily capture these credentials and potentially gain unauthorized access to systems. The plaintext transmission occurs at the application layer where the tool attempts to communicate with target systems to perform password analysis. This flaw directly violates fundamental network security principles and creates a man-in-the-middle attack vector. The vulnerability is classified under the broader category of information disclosure issues and represents a classic example of weak cryptographic implementation in network communications. Network security frameworks such as those outlined in the NIST SP 800-53 standards would categorize this as a significant weakness requiring immediate remediation.
The operational impact of this vulnerability extends beyond the immediate exposure of passwords during network transmission. Organizations using this demo software in their security assessment processes risk having their own authentication credentials intercepted by malicious actors monitoring network traffic. The exposure creates potential for privilege escalation attacks where attackers can leverage captured credentials to gain unauthorized access to systems that the password appraiser is attempting to evaluate. This creates a dangerous paradox where security testing tools become potential attack vectors themselves. The vulnerability also impacts the integrity of security assessments since compromised credentials could lead to false positives or negatives in password strength evaluations. In enterprise environments, this flaw could enable attackers to establish persistent access to network resources while the organization believes they are conducting legitimate security testing. The attack surface is further expanded because the vulnerability affects not only the demo version but potentially the full application if similar implementation flaws exist in the production release.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term architectural improvements to prevent similar issues in future software development. The most effective immediate solution involves implementing secure communication protocols such as tls or ssl encryption for all network transmissions containing sensitive information. The application should be modified to enforce encrypted connections for password transmission and authentication data exchange. Organizations should implement network segmentation and monitoring to detect and prevent unauthorized packet capture activities. Additionally, the software should be updated to include proper authentication token handling and credential obfuscation techniques. Security controls such as those recommended in the MITRE ATT&CK framework should be implemented to monitor for suspicious network activity and credential exposure. The vulnerability highlights the importance of secure coding practices and the necessity of conducting thorough security reviews during software development lifecycle phases. Organizations should also consider implementing network access controls and intrusion detection systems to identify potential exploitation attempts. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other network applications and systems that may be vulnerable to plaintext credential exposure.