A potential security issue exists in the Install Wizard functionality of the DNN portal framework. DNN has created a fix which will be in the DNN Platform 7.4.1 release due out in early June. The security issues only affects 'a small subset of users'.
 

Security Suggestion

To ensure your site’s security, the following files should be deleted:

• InstallWizard.aspx
• InstallWizard.aspx.cs

 

Hosted Clients

As part of Accord's proactive security policy, both of these files have already been deleted from all Eval and SaaS sites and no action is required by our Hosted Clients.
 

Self Hosted Clients

Self Hosted clients may want to delete these files or wait to upgrade to 7.4.1 in early June.

More information can be found on the DNN Software website:
http://www.dnnsoftware.com/community-blog/cid/155198/workaround-for-potential-security-issue