CVE-2012-1602 in NextBBS
Summary
by MITRE
user.php in NextBBS 0.6 allows remote attackers to bypass authentication and gain administrator access by setting the userkey cookie to 1.
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Analysis
by VulDB Data Team • 02/22/2019
The vulnerability identified as CVE-2012-1602 resides in the user.php script of NextBBS version 0.6, representing a critical authentication bypass flaw that fundamentally compromises system security. This issue stems from improper validation of user authentication state within the application's session management mechanism, specifically targeting the userkey cookie parameter that should normally serve as a secure identifier for authenticated users. The vulnerability operates through a simple yet devastating manipulation of cookie values, where an attacker can trivially elevate their privileges by setting the userkey cookie to the value of 1, effectively granting administrative access to any user who can manipulate this parameter.
The technical implementation of this vulnerability demonstrates a classic lack of input validation and privilege verification within the application's authentication flow. When the user.php script processes requests, it fails to properly verify whether the userkey cookie corresponds to an actual authenticated user account with appropriate permissions. Instead, the application treats any userkey value of 1 as equivalent to administrator privileges, creating a direct pathway for unauthorized access. This flaw represents a violation of the principle of least privilege and demonstrates poor security architecture where a simple integer value can bypass complex authentication mechanisms. The vulnerability is classified under CWE-287, which addresses improper handling of authentication tokens, and aligns with ATT&CK technique T1078.101 focusing on valid accounts for privilege escalation.
The operational impact of this vulnerability extends far beyond simple unauthorized access, as it provides attackers with complete administrative control over the NextBBS installation. Once an attacker establishes administrative privileges through this cookie manipulation, they can modify user accounts, alter forum content, access sensitive data, and potentially use the compromised system as a launching point for further attacks within the network. The simplicity of exploitation means that even basic attackers can leverage this vulnerability without requiring advanced technical skills or extensive reconnaissance. This creates a significant risk for organizations deploying NextBBS 0.6, as the vulnerability can be exploited through simple web browser manipulation without requiring specialized tools or deep knowledge of the application's internals.
Mitigation strategies for CVE-2012-1602 must address both the immediate vulnerability and underlying architectural issues that enabled it. The most effective immediate solution involves implementing proper input validation and privilege checking within the user.php script, ensuring that the userkey cookie value is verified against legitimate user sessions and that administrative privileges are confirmed through proper authentication mechanisms rather than simple value comparisons. Organizations should also implement proper session management practices including secure cookie attributes, session timeout mechanisms, and regular session validation checks. Additionally, the application should be updated to a patched version that properly implements authentication controls, as NextBBS 0.6 is an outdated version that likely contains additional vulnerabilities. Network segmentation and monitoring solutions should be deployed to detect suspicious cookie manipulation attempts, while security audits should verify that similar privilege escalation vulnerabilities do not exist in other components of the application stack. The remediation process should also include implementing proper access controls and ensuring that administrative functions require explicit authentication and authorization checks rather than relying on simple cookie value comparisons.