CVE-2008-6540 in DotNetNuke
Summary
by MITRE
DotNetNuke before 4.8.2, during installation or upgrade, does not warn the administrator when the default (1) ValidationKey and (2) DecryptionKey values cannot be modified in the web.config file, which allows remote attackers to bypass intended access restrictions by using the default keys.
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Analysis
by VulDB Data Team • 04/29/2026
The vulnerability described in CVE-2008-6540 affects DotNetNuke content management systems prior to version 4.8.2 and represents a critical security flaw in the application's installation and upgrade processes. This weakness stems from the application's failure to properly alert administrators when default cryptographic keys cannot be modified during system deployment, creating a persistent security risk that can be exploited by remote attackers. The vulnerability specifically impacts the web.config file configuration where the ValidationKey and DecryptionKey values are stored, which are essential components for maintaining application security and integrity.
The technical flaw lies in the insufficient validation and warning mechanisms implemented during DotNetNuke's installation and upgrade procedures. When administrators attempt to install or upgrade the system, the application does not provide adequate feedback when it detects that the default cryptographic keys cannot be properly modified or replaced. This occurs because the system relies on default values that are publicly known and easily accessible, allowing malicious actors to exploit this predictable configuration. The vulnerability is classified under CWE-310 as "Cryptographic Issues" and more specifically relates to CWE-312, which addresses "Cleartext Storage of Sensitive Information" and CWE-319, "Cleartext Transmission of Sensitive Information" in the context of cryptographic key management.
The operational impact of this vulnerability is severe and multifaceted, as it allows remote attackers to bypass intended access restrictions by leveraging the default cryptographic keys. Attackers can use these known default values to perform various malicious activities including session hijacking, data manipulation, and unauthorized access to protected application features. The vulnerability creates a backdoor that can be exploited across multiple attack vectors, potentially leading to full system compromise and data breaches. According to ATT&CK framework, this vulnerability maps to T1566 for "Phishing" and T1078 for "Valid Accounts" as attackers can exploit the predictable keys to gain unauthorized access to administrative functions and user data.
Organizations running vulnerable versions of DotNetNuke face significant risks including unauthorized data access, session manipulation, and potential complete system takeover. The default keys provide attackers with the means to decrypt sensitive information and manipulate application behavior without proper authentication. This vulnerability is particularly dangerous because it persists through system upgrades and installations, making it difficult to detect and remediate. The impact extends beyond immediate security breaches to include compliance violations, regulatory penalties, and potential legal consequences for organizations that fail to address this vulnerability promptly.
The recommended mitigations for CVE-2008-6540 involve immediate upgrading to DotNetNuke version 4.8.2 or later, which addresses the key modification issue through enhanced validation and warning mechanisms. Administrators should also manually verify that cryptographic keys in the web.config file have been properly modified and are unique to their specific deployment environment. Additional protective measures include implementing proper access controls, monitoring system logs for suspicious activities, and conducting regular security assessments to ensure that cryptographic configurations remain secure and properly implemented. Organizations should also consider implementing network segmentation and intrusion detection systems to monitor for potential exploitation attempts targeting this specific vulnerability.