CVE-2006-6969 in Jetty
Summary
by MITRE
Jetty before 4.2.27, 5.1 before 5.1.12, 6.0 before 6.0.2, and 6.1 before 6.1.0pre3 generates predictable session identifiers using java.util.random, which makes it easier for remote attackers to guess a session identifier through brute force attacks, bypass authentication requirements, and possibly conduct cross-site request forgery attacks.
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Analysis
by VulDB Data Team • 08/19/2018
The vulnerability identified as CVE-2006-6969 represents a critical weakness in the Jetty web server implementation that affects multiple version branches including 4.2.x before 4.2.27, 5.1.x before 5.1.12, 6.0.x before 6.0.2, and 6.1.x before 6.1.0pre3. This issue stems from the improper generation of session identifiers that rely on the java.util.Random class, creating a predictable sequence of session tokens that can be easily exploited by malicious actors. The fundamental flaw lies in the cryptographic weakness of the random number generation algorithm used by the web server to create unique session identifiers for user authentication sessions. This predictable session generation mechanism directly violates security best practices and creates significant risks for web applications relying on Jetty as their underlying server infrastructure.
The technical implementation of this vulnerability demonstrates a failure in entropy generation and cryptographic randomness within the Jetty server's session management system. When the java.util.Random class is utilized for session identifier creation, it produces pseudo-random sequences that can be reconstructed through statistical analysis or brute force techniques. This weakness specifically targets the session management component of the web server, which is responsible for maintaining user authentication states across multiple HTTP requests. The predictable nature of these identifiers allows attackers to systematically guess valid session tokens without requiring legitimate access credentials, effectively bypassing authentication mechanisms that should protect application resources. This vulnerability operates at the application layer and can be classified under CWE-330 as the use of insufficiently random values, while also aligning with CWE-310 for weak cryptographic randomness.
The operational impact of this vulnerability extends beyond simple authentication bypass to encompass broader security implications including potential cross-site request forgery attacks and unauthorized access to protected resources. Attackers can leverage the predictable session identifiers to impersonate legitimate users, access restricted areas of web applications, and potentially escalate privileges within the affected systems. The vulnerability creates an attack surface that allows remote exploitation without requiring any special privileges or access to system resources, making it particularly dangerous in environments where Jetty serves critical web applications. The brute force nature of the attack means that even with moderate computational resources, attackers can systematically work through potential session identifiers to gain unauthorized access to user sessions and application functionality. This weakness can be mapped to ATT&CK technique T1566 for credential access through social engineering and T1190 for exploitation of vulnerabilities in web applications.
The mitigation strategies for this vulnerability require immediate implementation of patched versions of the Jetty server software that address the session identifier generation issue through proper cryptographic random number generation. Organizations should upgrade to versions that utilize secure random number generators such as java.security.SecureRandom instead of java.util.Random for session identifier creation. Additionally, administrators should implement supplementary security measures including session timeout configurations, secure cookie attributes, and regular monitoring for suspicious session activity. The remediation process should also include comprehensive testing to ensure that the patched implementations properly generate cryptographically secure session identifiers and that existing session tokens are invalidated during the upgrade process. Security teams should also consider implementing session management policies that enforce additional authentication factors and monitor for patterns consistent with session prediction attacks.