The Benefits of Credentialed Scanning and Auditing
We've covered the advantages of credentialed vulnerability scanning and configuration auditing in previous blog posts, but I want to recap some of the benefits:
- Getting Around Firewalls - Whether you are scanning through network or host firewalls, credentialed scans require less ports to be open between the scanner and the target(s) and require less network bandwidth and target resources.
- Finding Localized Vulnerabilities - Several vulnerabilities, including those being exploited by attackers and penetration testers alike, are not accessible over the network but present themselves in end-user software ranging from web browsers, PDF readers and office suites. By performing a credentialed scan, Nessus is able to find vulnerabilities that requires user interaction to trigger exploitation in local software.
- Verifying Settings & Configurations - Through either Nessus plugins or configuration auditing, you can answer questions about the state of your systems. For example, if you want to know who has either local or domain administrative rights to your systems, there are plugins that report the list of users. Want to know what type of USB devices are in use in your environment or which systems have modems connected? There are plugins that test for those conditions as well. With configuration auditing, you can check any registry entry on a Windows system for a specific value or check the values on entries in configuration files on Linux/UNIX systems.
Making It Easier
Convincing your systems administrators to allow credentialed scanning in your environment can be difficult at first. Administrators are typically reluctant to provide administrative level credentials required for accurate local scanning and/or enable the required services and configurations. However, I strongly recommend presenting them with the benefits listed above to help plead your case. For Windows systems, there are two features that can make it easier to perform credentialed scans, one of which is a brand new addition to Nessus:
- Start the registry service during the scan - This option will enable the remote registry service for the purposes of the scan, then disable it when the scan finishes.
- Enable administrative shares during the scan (NEW) - This option will enable the C$ and ADMIN$ shares for the duration of the scan, then disable them when the scan finishes.