CVE-2025-52488: DNN Platform NTLM Hash Disclosure Flaw

CVE-2025-52488 Overview

CVE-2025-52488 is an information disclosure vulnerability in DNN (formerly DotNetNuke), an open-source web content management platform (CMS) in the Microsoft ecosystem. The vulnerability allows attackers to potentially expose NTLM hashes to a third-party SMB server through a specially crafted series of malicious interactions. This vulnerability affects versions 6.0.0 through 10.0.0 of the DNN.PLATFORM and has been addressed in version 10.0.1.

Critical Impact

Successful exploitation could expose NTLM authentication hashes, enabling credential theft, pass-the-hash attacks, or offline password cracking that may lead to full system compromise.

Affected Products

• DNN (DotNetNuke) Platform versions 6.0.0 to 10.0.0
• dnnsoftware dotnetnuke installations within the affected version range
• Self-hosted and cloud-deployed DNN CMS instances

Discovery Timeline

• 2025-06-21 - CVE CVE-2025-52488 published to NVD
• 2025-09-15 - Last updated in NVD database

Technical Details for CVE-2025-52488

Vulnerability Analysis

This vulnerability is classified under CWE-200 (Information Exposure), representing an information disclosure weakness that enables unauthorized access to sensitive authentication data. The flaw exists in how DNN.PLATFORM handles certain requests that can be manipulated to force the server to authenticate against an attacker-controlled SMB server, thereby leaking NTLM hashes.

The attack can be initiated remotely over the network without requiring any prior authentication or user interaction. The vulnerability has a changed scope, meaning exploitation of the vulnerable component can impact resources beyond its security scope, potentially affecting other systems that rely on the compromised credentials.

Root Cause

The root cause stems from improper handling of user-controlled input that can trigger SMB authentication attempts to external servers. When a DNN installation processes certain specially crafted requests, the underlying Windows server may attempt to authenticate to a remote SMB share, inadvertently transmitting NTLM credentials. This behavior exposes the authentication hash to any attacker who controls the destination SMB server, creating a significant credential exposure risk.

Attack Vector

The attack leverages the network-accessible nature of DNN CMS installations. An attacker can craft malicious requests that cause the DNN server to initiate outbound SMB connections to an attacker-controlled server. When the Windows server attempts to authenticate to this malicious SMB share, it sends NTLM authentication data. The attacker captures these hashes using tools like Responder or custom SMB servers, which can then be:

1. Used directly in pass-the-hash attacks to authenticate as the compromised user
2. Subjected to offline brute-force or dictionary attacks to recover plaintext passwords
3. Relayed to other network services accepting NTLM authentication

The vulnerability requires no privileges and no user interaction, making it particularly dangerous for internet-facing DNN installations.

Detection Methods for CVE-2025-52488

Indicators of Compromise

• Unusual outbound SMB (TCP port 445) connection attempts from the DNN web server to external IP addresses
• Unexpected NTLM authentication events in Windows Security logs originating from the IIS application pool identity
• Network traffic analysis showing SMB protocol communication to non-corporate IP ranges
• Failed authentication attempts appearing in target systems using credentials from the DNN server

Detection Strategies

• Monitor outbound network traffic from web servers for SMB connections (TCP 445, TCP 139) to non-whitelisted destinations
• Implement network segmentation to restrict outbound SMB traffic from DMZ and web-tier servers
• Deploy endpoint detection rules to alert on w3wp.exe or DNN-related processes initiating SMB connections
• Review IIS logs for suspicious request patterns that may indicate exploitation attempts

Monitoring Recommendations

• Configure SIEM alerts for outbound SMB traffic originating from web server subnets
• Enable Windows Security Event logging (Event ID 4648, 4624) on DNN servers and correlate with network events
• Deploy network detection signatures for NTLM relay attack patterns
• Establish baseline network behavior for DNN servers and alert on deviations involving SMB protocols

How to Mitigate CVE-2025-52488

Immediate Actions Required

• Upgrade DNN Platform to version 10.0.1 or later immediately
• Block outbound SMB traffic (TCP ports 445 and 139) from web servers at the network firewall level
• Review authentication logs for signs of credential compromise following potential exposure
• Consider resetting service account credentials used by DNN application pools if exploitation is suspected

Patch Information

DNNSoftware has released version 10.0.1 which addresses this vulnerability. Organizations should prioritize upgrading from affected versions (6.0.0 through 10.0.0) to the patched release. The security advisory with additional details is available at the GitHub Security Advisory for GHSA-mgfv-2362-jq96.

Workarounds

• Block all outbound SMB traffic (TCP 445/139) from DNN web servers using host-based or network firewalls
• Configure Windows Firewall rules to prevent w3wp.exe from initiating outbound SMB connections
• Deploy network segmentation to isolate web servers and restrict their ability to reach internal SMB resources
• Consider implementing SMB signing and disabling NTLMv1 to reduce the impact of any captured hashes

# Windows Firewall rule to block outbound SMB from IIS
netsh advfirewall firewall add rule name="Block Outbound SMB from IIS" dir=out action=block protocol=tcp remoteport=445 program="%systemroot%\system32\inetsrv\w3wp.exe"

# Additional rule for NetBIOS
netsh advfirewall firewall add rule name="Block Outbound NetBIOS from IIS" dir=out action=block protocol=tcp remoteport=139 program="%systemroot%\system32\inetsrv\w3wp.exe"