CVE-2025-52488 is a high-severity vulnerability affecting the Dnn.Platform, an open-source web content management system widely used within the Microsoft ecosystem. This vulnerability exists in versions from 6.0.0 up to, but not including, 10.0.1. The core issue involves the exposure of NTLM (NT LAN Manager) hashes to an unauthorized third-party SMB (Server Message Block) server. Specifically, through a specially crafted sequence of interactions with the vulnerable Dnn.Platform instance, an attacker can cause the system to leak NTLM authentication hashes. These hashes can then be captured by the attacker’s SMB server, potentially enabling offline brute-force attacks to recover plaintext credentials or to perform relay attacks. The vulnerability is classified under CWE-200, indicating exposure of sensitive information to unauthorized actors. The CVSS v3.1 base score is 8.6, reflecting a network attack vector with low attack complexity, no privileges required, no user interaction, and a scope change, with high confidentiality impact but no impact on integrity or availability. The vulnerability has been patched in version 10.0.1 of Dnn.Platform. There are currently no known exploits in the wild, but the ease of exploitation and the critical nature of leaked NTLM hashes make this a significant threat. Given the nature of NTLM hashes, attackers gaining these could leverage lateral movement within networks, escalate privileges, or compromise additional systems, especially in environments relying on NTLM authentication. The vulnerability does not require authentication or user interaction, increasing its risk profile. The exposure occurs over the network, making remote exploitation feasible without prior access.

For European organizations, the exposure of NTLM hashes poses a substantial risk, particularly for enterprises and public sector entities that utilize Dnn.Platform for web content management. Successful exploitation could lead to credential compromise, enabling attackers to impersonate legitimate users, escalate privileges, and move laterally within corporate networks. This can result in unauthorized access to sensitive data, disruption of business processes, and potential regulatory non-compliance under GDPR due to data breaches. Organizations relying on NTLM authentication are especially vulnerable, as compromised hashes can facilitate relay attacks or offline cracking. The impact is magnified in sectors with high-value targets such as finance, government, healthcare, and critical infrastructure, where unauthorized access could lead to significant operational and reputational damage. Additionally, the vulnerability’s network-based exploitation vector means that external attackers can attempt to exploit internet-facing Dnn.Platform instances, increasing the attack surface. The lack of known exploits in the wild currently provides a window for remediation, but the high CVSS score and ease of exploitation suggest that threat actors may develop exploits rapidly. Failure to patch could lead to widespread compromise, especially in environments where patch management is slow or where legacy versions of Dnn.Platform are still in use.

1. Immediate upgrade of all Dnn.Platform instances to version 10.0.1 or later, where the vulnerability is patched, is the most effective mitigation. 2. For environments where immediate upgrade is not feasible, implement network-level controls to restrict outbound SMB traffic from web servers hosting Dnn.Platform, preventing NTLM hash leakage to unauthorized SMB servers. 3. Employ network segmentation to isolate web servers from sensitive internal networks, limiting lateral movement opportunities if credentials are compromised. 4. Monitor network traffic for unusual SMB connection attempts or unexpected outbound SMB traffic from web servers, using IDS/IPS or network monitoring tools. 5. Enforce strong password policies and consider disabling NTLM authentication where possible in favor of more secure protocols like Kerberos. 6. Conduct regular audits of Dnn.Platform versions across the organization to identify and remediate outdated instances. 7. Implement multi-factor authentication (MFA) for all critical systems to reduce the impact of credential compromise. 8. Educate IT and security teams about this vulnerability and ensure incident response plans include steps for potential NTLM hash exposure incidents. 9. Review and harden SMB server configurations to prevent unauthorized SMB connections and limit exposure to relay attacks. 10. Apply principle of least privilege to service accounts and users interacting with Dnn.Platform to minimize potential damage from compromised credentials.