CVE-1999-0699 in Sapphire Web
Summary
by MITRE
The Bluestone Sapphire web server allows session hijacking via easily guessable session IDs.
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Analysis
by VulDB Data Team • 04/21/2026
The vulnerability described in CVE-1999-0699 represents a critical security flaw in the Bluestone Sapphire web server implementation that directly enables session hijacking attacks. This issue stems from the server's inadequate randomization of session identifiers, creating predictable session tokens that malicious actors can easily guess and exploit. The vulnerability affects the fundamental authentication and session management mechanisms that protect user sessions and maintain secure access to web applications.
The technical flaw manifests in the session ID generation algorithm used by the Bluestone Sapphire web server, which fails to implement proper cryptographic randomness. Session identifiers should be generated using cryptographically secure random number generators to ensure unpredictability and prevent attackers from guessing valid session tokens. When session IDs are predictable, attackers can perform session hijacking by simply guessing valid session identifiers that correspond to active user sessions, effectively impersonating legitimate users without requiring valid credentials. This vulnerability directly violates the principles outlined in CWE-330, which addresses the use of insufficiently random values in security contexts.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it enables attackers to perform complete session takeover attacks that can compromise user privacy, data integrity, and system availability. Once an attacker successfully hijacks a session, they gain access to all the privileges and permissions associated with that user account, potentially allowing them to view sensitive information, modify data, or perform actions on behalf of the legitimate user. The vulnerability is particularly dangerous because it does not require any special privileges or complex attack vectors - simply guessing a session ID is sufficient to gain unauthorized access. This aligns with the attack pattern described in the MITRE ATT&CK framework under T1566 for credential access and T1078 for valid accounts.
The implications of this vulnerability are particularly severe in environments where sensitive data is processed or where users have elevated privileges, as session hijacking can lead to complete system compromise. Organizations running Bluestone Sapphire web servers are vulnerable to various attack scenarios including automated guessing tools that can rapidly test potential session identifiers, making the attack surface significantly larger than initially apparent. The vulnerability demonstrates a fundamental flaw in the security architecture of the web server implementation and highlights the critical importance of proper session management and cryptographic randomness in web application security.
Mitigation strategies for this vulnerability require immediate implementation of cryptographic random session ID generation mechanisms that comply with industry standards such as those outlined in NIST SP 800-90A for random number generation. Organizations should upgrade their web server implementations to versions that properly implement secure session management or apply patches that address the predictable session ID generation issue. Additionally, implementing session timeout mechanisms, secure session cookie attributes, and monitoring for suspicious session activity can help reduce the impact of potential exploitation. The vulnerability also underscores the need for regular security assessments and adherence to secure coding practices that prevent the use of predictable values in security-critical contexts, as recommended by the OWASP Top Ten security framework.