6.3.3.30 Ensure successful and unsuccessful attempts to use the usermod command are collected

Information

The operating system must generate audit records for successful/unsuccessful uses of the usermod command.

The usermod command modifies the system account files to reflect the changes that are specified on the command line. Without generating audit records that are specific to the security and 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).

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

Solution

Note:

- The -w option is deprecated and the rule should be updated in accordance with the Remediation Procedure.
- For best performance, the arch field should be supplied in the rule. The individual permissions will cause the selection of specific system calls that use that kind of access. Not supplying the arch will cause the selection of all system calls which will affect performance as all system calls will be evaluated.

- Edit or create a file in the /etc/audit/rules.d/ directory, ending inrules extension, with the relevant rules to monitor successful and unsuccessful attempts to use the usermod command.

Example:

# printf "
-a always,exit -F arch=b64 -S all -F path=/usr/sbin/usermod -F perm=x -F auid>=1000 -F auid!=unset -k usermod
" >> /etc/audit/rules.d/50-usermod.rules unset

Note : The auid>= value should be set to the same value as UID_MIN value in /etc/login.defs

<xhtml:ol start="2"> - Merge and load the rules into active configuration:

# augenrules --load <xhtml:ol start="3"> - Check if reboot is required:

# if [[ $(auditctl -s | grep "enabled") =~ "2" ]]; then printf "Reboot required to load rules\n"; fi

See Also

https://workbench.cisecurity.org/benchmarks/23593