CVE-2018-15811

What is DotNetNuke (DNN)?

DotNetNuke (rebranded DNN Platform) is an open-source content management system and web application framework built on Microsoft's .NET stack, widely used for corporate intranets, public-facing websites, and web portals. Like most CMS platforms, it relies on cryptographic protections to keep internal state — input parameters passed between pages, view state, or similar tokens — safe from tampering by end users.

Overview

CVE-2018-15811 is an inadequate encryption strength vulnerability in DotNetNuke resulting from use of a weak encryption algorithm to protect certain input parameters. Because the algorithm used does not provide sufficient cryptographic strength, an attacker can potentially recover the key or otherwise break the encryption, allowing tampering with values that the application trusts to be protected from client-side manipulation. Notably, the initial fix for this issue was incomplete — the related follow-up vulnerability CVE-2018-18325 was later published to address the remaining gap.

Technical Details

The flaw (CWE-326, Inadequate Encryption Strength) means the confidentiality/integrity guarantee that DNN relies on for these input parameters can be broken through cryptanalysis or brute-force techniques against the weak algorithm, rather than through any application logic bug. Once broken, an attacker can craft their own valid-looking encrypted parameter values, potentially bypassing intended access restrictions or manipulating application behavior — the CVSS vector reflects a confidentiality impact (7.5) with no additional privileges or user interaction required to attempt exploitation.

Discovery

The vulnerability was addressed through DNN's standard security release process; the follow-up CVE-2018-18325 indicates the DNN team or the broader community identified that the original patch did not fully close the underlying weakness.

Exploitation Context

CISA's KEV entry confirms this vulnerability has been exploited in the wild. Because the flaw affects a widely-deployed CMS platform and the first patch attempt was incomplete, organizations that patched only for CVE-2018-15811 without also applying the CVE-2018-18325 fix may have remained exposed for longer than expected.

Remediation

1. Upgrade to the DNN Platform version that resolves both CVE-2018-15811 and its follow-up CVE-2018-18325 — patching one without the other leaves the underlying weakness only partially addressed.
2. Confirm the specific cryptographic configuration recommended in DNN's security release notes is applied, not just the version bump.
3. Rotate any application secrets or keys that may have been protected by the weak algorithm, out of caution.
4. Monitor for unusual parameter values or tampering attempts in application logs.
5. Keep DNN installations on a current, actively supported release line to receive future cryptographic hardening updates.