CVE-2008-6549 in MoinMoin
Summary
by MITRE
The password_checker function in config/multiconfig.py in MoinMoin 1.6.1 uses the cracklib and python-crack features even though they are not thread-safe, which allows remote attackers to cause a denial of service (segmentation fault and crash) via unknown vectors.
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Analysis
by VulDB Data Team • 09/15/2017
The vulnerability identified as CVE-2008-6549 affects MoinMoin version 1.6.1 and stems from a critical design flaw in the password_checker function located within the config/multiconfig.py file. This function incorporates cracklib and python-crack libraries to validate password strength, but fails to account for the thread-unsafe nature of these cryptographic libraries. The implementation creates a dangerous scenario where concurrent access to the password validation functionality can lead to system instability and complete service disruption.
The technical root cause of this vulnerability lies in the improper handling of thread-safety concerns within the password validation subsystem. When multiple users attempt to create or modify passwords simultaneously, the cracklib and python-crack libraries encounter race conditions that result in segmentation faults and subsequent system crashes. This behavior represents a classic example of improper resource management and concurrency control in security-critical components. The vulnerability manifests as a denial of service condition where legitimate users cannot access the system due to the crashing of the password checking mechanism, effectively creating a denial of service scenario that impacts availability.
From an operational perspective, this vulnerability presents a significant risk to MoinMoin wiki deployments where multiple concurrent users might be attempting authentication or password changes simultaneously. The impact extends beyond simple service disruption to potentially compromise the entire wiki platform's availability, as the crash occurs at the core authentication layer. Attackers can exploit this weakness by crafting specific requests that trigger concurrent access patterns, leading to repeated system crashes and making the service unusable for legitimate users. This vulnerability directly maps to CWE-362, which describes concurrent execution use of a resource without proper synchronization, and represents a clear violation of secure coding practices.
The security implications of this vulnerability extend to the broader threat landscape, particularly when considering the ATT&CK framework's approach to privilege escalation and denial of service techniques. An attacker exploiting this vulnerability can effectively render the wiki platform unusable, potentially disrupting business operations and information access. The thread-safety issue creates a condition where the system becomes unstable under normal load conditions, making it particularly dangerous in production environments where user concurrency is expected. Organizations using MoinMoin 1.6.1 are particularly vulnerable because the flaw exists in the core authentication mechanism rather than in peripheral features.
Mitigation strategies for this vulnerability require immediate attention through several approaches. The most effective solution involves upgrading to a patched version of MoinMoin where the thread-safety issues have been addressed through proper synchronization mechanisms or by replacing the vulnerable libraries with thread-safe alternatives. System administrators should implement temporary workarounds such as disabling password strength checking or implementing rate limiting on authentication attempts to prevent exploitation. Additionally, organizations should consider implementing monitoring solutions to detect unusual patterns of authentication failures that might indicate exploitation attempts. The fix typically requires modifications to the password_checker function to ensure proper locking mechanisms are in place when accessing the cracklib and python-crack libraries, preventing concurrent access that leads to system instability.