Successful/unsuccessful uses of the usermod command in RHEL 8 must generate an audit record.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-230463	RHEL-08-030560	SV-230463r599732_rule		Medium

Description
Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "usermod" command modifies the system account files to reflect the changes that are specified on the command line. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210

Description

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one. Audit records can be generated from various components within the information system (e.g., module or policy filter). The "usermod" command modifies the system account files to reflect the changes that are specified on the command line. When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way. Satisfies: SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210

STIG	Date
Red Hat Enterprise Linux 8 Security Technical Implementation Guide	2020-11-25

Details

Check Text ( C-33132r568135_chk )
Verify that an audit event is generated for any successful/unsuccessful use of the "usermod" command by performing the following command to check the file system rules in "/etc/audit/audit.rules": $ sudo grep -w usermod /etc/audit/audit.rules -a always,exit -F path=/usr/sbin/usermod -F perm=x -F auid>=1000 -F auid!=unset -k privileged-usermod If the command does not return a line, or the line is commented out, this is a finding.

Check Text ( C-33132r568135_chk )

Verify that an audit event is generated for any successful/unsuccessful use of the "usermod" command by performing the following command to check the file system rules in "/etc/audit/audit.rules":

$ sudo grep -w usermod /etc/audit/audit.rules

-a always,exit -F path=/usr/sbin/usermod -F perm=x -F auid>=1000 -F auid!=unset -k privileged-usermod

If the command does not return a line, or the line is commented out, this is a finding.

Fix Text (F-33107r568136_fix)
Configure the audit system to generate an audit event for any successful/unsuccessful uses of the "usermod" command by adding or updating the following rule in the "/etc/audit/rules.d/audit.rules" file: -a always,exit -F path=/usr/sbin/usermod -F perm=x -F auid>=1000 -F auid!=unset -k privileged-usermod The audit daemon must be restarted for the changes to take effect.