Configuration assessment

Automated Security Configuration Assessment (SCA) is an essential capability to improve the enterprise security posture, and to reduce its attack surface. Wazuh SCA module helps maintain a standard configuration through the monitored endpoints. This is done via pre-defined checks based on Center of Internet Security (CIS) hardening guides.

When the SCA module is enabled, the Wazuh agent performs scans periodically, reporting misconfigurations in the monitored system. Those scans assess the configuration of the system by means of policy files, which contain a set of checks to be run. For example, an SCA check could inspect the filesystem configuration, look for the presence of a software update or security patch, see that the local firewall is enabled, identify unnecessary running services, or verify the users’ password policy.

Policies for the SCA scans are written in YAML format, allowing users to quickly understand them. Using SCA syntax, users can extend the existing policies to fit their needs or write new ones. Each policy contains a set of checks, and each check has one or more rules. For example, a rule can be used to look for the existence of a file, a directory, a Windows registry key, a running process, etc. It can also run a command and check its output against a regular expression.

Linux SCA rule example:

- id: 5546
  title: "Ensure IP forwarding is disabled"
  description: "The net.ipv4.ip_forward flag is used to tell the system whether it can forward packets or not."
  rationale: "Setting the flag to 0 ensures that a system with multiple interfaces (for example, a hard proxy), will never be able to forward packets, and therefore, never serve as a router."
  remediation: "Set the following parameter in /etc/sysctl.conf or a /etc/sysctl.d/* file: net.ipv4.ip_forward = 0 and set the active kernel parameters."
  compliance:
    - cis: ["3.1.1"]
    - cis_csc: ["3", "11"]
    - pci_dss: ["2.2.4"]
    - nist_800_53: ["CM.1"]
  condition: all
  rules:
    - 'c:sysctl net.ipv4.ip_forward -> r:^net.ipv4.ip_forward\s*=\s*0$'
    - 'c:grep -Rh net\.ipv4\.ip_forward /etc/sysctl.conf /etc/sysctl.d -> r:^net.ipv4.ip_forward\s*=\s*0$'

Windows SCA rule example:

- id: 14038
  title: "Ensure Microsoft Firewall is enabled"
  compliance:
    - pci_dss: ["10.6.1", "1.4"]
    - hipaa: ["164.312.b", "164.312.a.1"]
    - nist_800_53: ["AU.6", "SC.7"]
    - tsc: ["CC6.1", "CC6.8", "CC7.2", "CC7.3", "CC6.7"]
  condition: all
  rules:
    - 'r:HKEY_LOCAL_MACHINE\software\policies\microsoft\windowsfirewall\domainprofile -> enablefirewall -> 1'

macOS SCA rule example:

- id: 8522
  title: "Ensure nfs server is not running"
  description: "macOS can act as an NFS fileserver. NFS sharing could be enabled to allow someone on another computer to mount shares and gain access to information from the user's computer. File sharing from a user endpoint has long been considered questionable and Apple has removed that capability from the GUI. NFSD is still part of the Operating System and can be easily turned on to export shares and provide remote connectivity to an end user computer."
  rationale: "File serving should not be done from a user desktop, dedicated servers should be used.  Open ports make it easier to exploit the computer."
  remediation: "Ensure that the NFS Server is not running and is not set to start at boot Stop the NFS Server: sudo nfsd disable    Remove the exported Directory listing: rm /etc/export"
  compliance:
    - cis: ["4.5"]
  condition: none
  rules:
    - 'p:nfsd'
    - 'p:/sbin/nfsd'
    - 'f:/etc/exports'

Below is an example of the results of a configuration assessment evaluation. Those can be obtained through the web user interface or by using the Wazuh RESTful API directly.

../../_images/use_case_sca.png

More information about security configuration assessment can be found at the user manual.