4.1.11 Ensure use of privileged commands is collected

Information

Monitor privileged programs (those that have the setuid and/or setgid bit set on execution) to determine if unprivileged users are running these commands.

Note: Systems may have been customized to change the default UID_MIN. To confirm the UID_MIN for your system, run the following command:

# awk '/^s*UID_MIN/{print $2}' /etc/login.defs

If your systems' UID_MIN is not 1000, replace audit>=1000 with audit>=<UID_MIN for your system> in the Audit and Remediation procedures.

Rationale:

Execution of privileged commands by non-privileged users could be an indication of someone trying to gain unauthorized access to the system.

Solution

To remediate this issue, the system administrator will have to execute a find command to locate all the privileged programs and then add an audit line for each one of them. The audit parameters associated with this are as follows:
-F path=' $1 ' - will populate each file name found through the find command and processed by awk. -F perm=x - will write an audit record if the file is executed. -F auid>=1000 - will write a record if the user executing the command is not a privileged user. -F auid!= 4294967295 - will ignore Daemon events
All audit records should be tagged with the identifier 'privileged'.
Run the following command replacing with a list of partitions where programs can be executed from on your system:

# find <partition> -xdev ( -perm -4000 -o -perm -2000 ) -type f | awk '{print
'-a always,exit -F path=' $1 ' -F perm=x -F auid>=1000 -F auid!=4294967295
-k privileged' }'

Edit or create a file in the /etc/audit/rules.d/ directory ending in .rules
Example: vi /etc/audit/rules.d/privileged.rules
And add all resulting lines to the file.

Additional Information:

Reloading the auditd config to set active settings requires the auditd service to be restarted, and may require a system reboot.

See Also

https://workbench.cisecurity.org/files/2971

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-6, CSCv6|5.1, CSCv7|5.1

Plugin: Unix

Control ID: d9fada0017b53908121389f24ccd4e5201bf4e2ef88cd01c50243c0c385b4622