- Red Hat
- Patch audit
- Compliance audit
On Red Hat distros Nessus executes the following commands which work with non-root accounts:
Compliance audit - Tenable provides a number compliance audit files based on various industry best practices or regulations. The audit files can be downloaded from support forums. Compliance scan require elevated permissions as Nessus reads various system files.
I generally opt for using elevated permissions in both types of scans.
Setting up an account used for scanning:
In most cases SSHing directly with root account is disabled (which is a good thing from security standpoint). To confirm if it's disabled we can check /etc/ssh/sshd_confing. We need to look for line reading: "PermiRootLogin". If it's commented out or set to "yes". Root login is possible.
I like leaving "Netstat SSH Scan" enabled to get a list of listening ports. Output from netstat is most accurate and least intrusive.
We need to enable actual local security checks as well as relevant settings. I recommend enabling the whole "Settings" family as it contains a number of useful plugins besides required "SSH Settings" plugin.
2. enable whole "settings" family
19506 Nessus Scan Information - info about the scan itself
12634 Authenticated Check: OS Name and Installed Package Enumeration - this plugin confirms whether supplied credentials worked and if Nessus was able to elevate permissions. If this plugin does not appear in scan output it means Nessus was unable to login to the target.
21745 Authentication Failure - Local Checks Not Run - If this plugin appears in scan output it means that authentication did not work and Nessus was unable to login to the target.
33851 Network daemons not managed by the package system - lists software installed - in most cases - from source. These application will not be updated by the package manager and may indicate compromised host.
25221 Remote listener enumeration - show processes listening on ports
33276 Enumerate MAC Addresses via SSH - shows L2 interfaces
22869 Software Enumeration (SSH) - list of installed software
25202 Enumerate IPv6 Interfaces via SSH - shows IPv6 interfaces
25203 Enumerate IPv4 Interfaces via SSH - shows IPv4 interfaces
This is all we need to do to create oatch audit policy.
Plugins - Compliance Audit policy:
For compliance audit we need to enable "Settings" family and plugin "21157 Unix Compliance Checks"
A desired audit policy file must be uploaded to Nessus server.