DotNetNuke (DNN) Remote Code Execution (RCE) Vulnerability via Weak Encryption Algorithm (CVE-2018-18325)
Executive & SecOps Summary
SECOPS ASSESSMENTDotNetNuke (DNN) Platform versions 9.2 through 9.2.2.
Attackers can bypass security controls due to weak encryption of input parameters, leading to .NET deserialization and Remote Code Execution (RCE) via malicious cookies.
Immediately upgrade the DNN Platform to version 9.3.0 or higher, and ensure secure machineKey configurations are applied.
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
Upgrade your DNN installation to version 9.3.0 or later. Use the following PowerShell commands to verify your current version and apply the upgrade package.
# Check the current version of DotNetNuke.dll to verify vulnerability status
(Get-Item 'C:\inetpub\wwwroot\bin\DotNetNuke.dll').VersionInfo.FileVersion
# Download and extract the secure DNN Platform upgrade package
Invoke-WebRequest -Uri 'https://github.com/dnnsoftware/Dnn.Platform/releases/download/v9.3.0/DNN_Platform_9.3.0_Upgrade.zip' -OutFile 'dnn_upgrade.zip'
Expand-Archive -Path 'dnn_upgrade.zip' -DestinationPath 'C:\inetpub\wwwroot\' -Force2. Temporary Workaround & Hardening Configuration
If an immediate upgrade is not feasible, harden the web.config file by explicitly defining secure, auto-generated, and isolated machine keys using strong encryption algorithms (AES).
<!-- Update the <machineKey> configuration within <system.web> in web.config -->
<configuration>
<system.web>
<machineKey validationKey='AutoGenerate,IsolateApps' decryptionKey='AutoGenerate,IsolateApps' validation='SHA1' decryption='AES' />
</system.web>
</configuration>3. Log Audit & IoC Verification Commands
Inspect IIS access logs for suspicious cookie values or serialized payloads that indicate exploitation attempts.
# Search for suspicious DNN cookie patterns in web server logs
grep -r -i 'dnn_' /var/log/iis/
# PowerShell command to scan IIS logs for potential deserialization attack vectors
Select-String -Path 'C:\inetpub\logs\LogFiles\W3SVC1\*.log' -Pattern '(?i)(__dnn_|dnn_IsMobile|Y29tcGFueXxlbXBsb3llZQ==)'Block Exploits Instantly with Managed Virtual Patching Rules
Can't patch production immediately? Deploy managed WAF rules at the edge to intercept RCE, SQLi, and deserialization payloads before they hit your origin server.
Technical Root Cause & Exploitation Mechanics
1. Vulnerability Overview & Root Cause
This vulnerability (CVE-2018-18325) exists in DotNetNuke (DNN) due to the use of a weak encryption algorithm to protect sensitive input parameters and cookie values. It is a direct result of an incomplete fix for the prior vulnerability CVE-2018-15811. The weak cryptographic implementation allows attackers to predict or forge encrypted parameters.
2. Exploitation Mechanics & Attack Scenario
An attacker exploits this flaw by crafting a malicious payload wrapped in a serialized .NET object, which is then encrypted using the weak algorithm parameters. When this payload is sent to the server (typically via HTTP cookies), the DNN application decrypts and deserializes the object. Because the input is not properly validated before deserialization, it triggers arbitrary code execution under the context of the IIS worker process.
3. Infrastructure & Business Impact
As a high-severity vulnerability listed in the CISA KEV catalog, this flaw poses an immediate threat of full system compromise. Successful exploitation allows unauthorized attackers to execute arbitrary commands, compromise backend databases, deploy ransomware, or pivot deeper into the internal corporate network.
Official Vendor Advisories & References
DNN (aka DotNetNuke) 9.2 through 9.2.2 uses a weak encryption algorithm to protect input parameters. NOTE: this issue exists because of an incomplete fix for CVE-2018-15811.
Frequently Asked SecOps Questions (CVE-2018-18325)
FAQQ1. How critical is CVE-2018-18325 and is it actively exploited in the wild?
CVE-2018-18325 is rated CVSS 7.5 (HIGH) with a 30-day EPSS exploitation probability of 74.1%. It is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, requiring immediate emergency remediation.
Q2. Which vendors and products are affected by CVE-2018-18325?
Primary impacted vendors include dnnsoftware across dotnetnuke. Scope summary: DotNetNuke (DNN) Platform versions 9.2 through 9.2.2 (due to incomplete fix for CVE-2018-15811)
Q3. What temporary mitigations or workarounds exist for CVE-2018-18325 before patching?
[Mitigation] Immediately upgrade the DNN Platform to version 9.3.0 or higher, and ensure secure machineKey configurations are applied. Follow the CLI remediation commands and interactive SecOps checklist on this page to restrict exposure prior to your maintenance window.
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