Nutanix AOS must use cryptographic mechanisms to protect the integrity of audit tools.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-254187	NUTX-OS-000990	SV-254187r846649_rule		High

Description
Protecting the integrity of the tools used for auditing purposes is a critical step toward ensuring the integrity of audit information. Audit information includes all information (e.g., audit records, audit settings, and audit reports) needed to successfully audit information system activity. Audit tools include, but are not limited to, vendor-provided and open source audit tools needed to successfully view and manipulate audit information system activity and records. Audit tools include custom queries and report generators. It is not uncommon for attackers to replace the audit tools or inject code into the existing tools with the purpose of providing the capability to hide or erase system activity from the audit logs. To address this risk, audit tools must be cryptographically signed to provide the capability to identify when the audit tools have been modified, manipulated, or replaced. An example is a checksum hash of the file or files.

Description

Protecting the integrity of the tools used for auditing purposes is a critical step toward ensuring the integrity of audit information. Audit information includes all information (e.g., audit records, audit settings, and audit reports) needed to successfully audit information system activity. Audit tools include, but are not limited to, vendor-provided and open source audit tools needed to successfully view and manipulate audit information system activity and records. Audit tools include custom queries and report generators. It is not uncommon for attackers to replace the audit tools or inject code into the existing tools with the purpose of providing the capability to hide or erase system activity from the audit logs. To address this risk, audit tools must be cryptographically signed to provide the capability to identify when the audit tools have been modified, manipulated, or replaced. An example is a checksum hash of the file or files.

STIG	Date
Nutanix AOS 5.20.x OS Security Technical Implementation Guide	2022-08-24

Details

Check Text ( C-57672r846647_chk )
Verify that Advanced Intrusion Detection Environment (AIDE) is properly configured to use cryptographic mechanisms to protect the integrity of audit tools. If AIDE is not installed, ask the System Administrator how file integrity checks are performed on the system. Verify the location of the seven auditing tools that require cryptographic protection with the following command: (auditctl, auditd, ausearch, aureport, autrace, augenrules, rsyslogd) $ sudo ls -al /usr/sbin/ \| egrep '(audit\|au\|rsys)' If the seven identified audit tools are not listed, this is a finding. Check the aide.conf file for the configured rule set. $ sudo grep -i "FIPSR =" /etc/aide.conf FIPSR = p+i+n+u+g+s+m+c+acl+selinux+xattrs+sha512 If the FIPSR rule set is commented out or does not display, this is a finding. Check to ensure that the root directory of the seven audit tools is configured to be monitored and that the proper rule set is applied to that directory (/usr/). $ sudo grep -i /usr /etc/aide.conf /usr FIPSR if the /usr directory is not listed or has a preceding '=' or '!' sign or the Rule Set is not set to FIPSR, this is a finding.

Check Text ( C-57672r846647_chk )

Verify that Advanced Intrusion Detection Environment (AIDE) is properly configured to use cryptographic mechanisms to protect the integrity of audit tools.

If AIDE is not installed, ask the System Administrator how file integrity checks are performed on the system.

Verify the location of the seven auditing tools that require cryptographic protection with the following command:
(auditctl, auditd, ausearch, aureport, autrace, augenrules, rsyslogd)

$ sudo ls -al /usr/sbin/ | egrep '(audit|au|rsys)'

If the seven identified audit tools are not listed, this is a finding.

Check the aide.conf file for the configured rule set.

$ sudo grep -i "FIPSR =" /etc/aide.conf
FIPSR = p+i+n+u+g+s+m+c+acl+selinux+xattrs+sha512

If the FIPSR rule set is commented out or does not display, this is a finding.

Check to ensure that the root directory of the seven audit tools is configured to be monitored and that the proper rule set is applied to that directory (/usr/).

$ sudo grep -i /usr /etc/aide.conf
/usr FIPSR

if the /usr directory is not listed or has a preceding '=' or '!' sign or the Rule Set is not set to FIPSR, this is a finding.

Fix Text (F-57623r846648_fix)
Configure AIDE on Nutanix AOS by running the following command: $ ncli cluster edit-cvm-security-params enable-aide=true