cyberstrikeus CIS Ubuntu Linux 16.04 LTS Benchmark v2.0.0 - Control 4.1.15
Profile
- Level: 2 - Server
- Level: 2 - Workstation
- Assessment Status: Automated
Description
sudo provides users with temporary elevated privileges to perform operations. Monitor the administrator with temporary elevated privileges and the operation(s) they performed.
Note: Reloading the auditd config to set active settings requires the auditd service to be restarted, and may require a system reboot.
Rationale
Creating an audit log of administrators with temporary elevated privileges and the operation(s) they performed is essential to reporting. Administrators will want to correlate the events written to the audit trail with the records written to sudo logfile to verify if unauthorized commands have been executed.
Impact
None.
Audit Procedure
Command Line
On a 32 bit system:
Run the following command to verify the rules are contained in a .rules file in the /etc/audit/rules.d/ directory:
grep actions /etc/audit/rules.d/*.rules
Verify the output includes:
-a exit,always -F arch=b32 -C euid!=uid -F euid=0 -Fauid>=1000 -F auid!=4294967295 -S execve -k actions
Run the following command to verify that rules are in the running auditd config:
auditctl -l | grep actions
Verify the output includes:
-a always,exit -F arch=b32 -S execve -C uid!=euid -F euid=0 -F auid>=1000 -F auid!=-1 -F key=actions
On a 64 bit system:
Run the following command to verify the rules are contained in a .rules file in the /etc/audit/rules.d/ directory:
grep actions /etc/audit/rules.d/*.rules
Verify the output includes:
-a exit,always -F arch=b64 -C euid!=uid -F euid=0 -Fauid>=1000 -F auid!=4294967295 -S execve -k actions
-a exit,always -F arch=b32 -C euid!=uid -F euid=0 -Fauid>=1000 -F auid!=4294967295 -S execve -k actions
Run the following command to verify that rules are in the running auditd config:
auditctl -l | grep actions
Verify the output includes:
-a always,exit -F arch=b64 -S execve -C uid!=euid -F euid=0 -F auid>=1000 -F auid!=-1 -F key=actions
-a always,exit -F arch=b32 -S execve -C uid!=euid -F euid=0 -F auid>=1000 -F auid!=-1 -F key=actions
Expected Result
Output should include the rules listed above for the appropriate architecture.
Remediation
Command Line
For 32 bit systems: Edit or create a file in the /etc/audit/rules.d/ directory ending in .rules.
Example: vi /etc/audit/rules.d/50-actions.rules
Add the following line:
-a exit,always -F arch=b32 -C euid!=uid -F euid=0 -Fauid>=1000 -F auid!=4294967295 -S execve -k actions
For 64 bit systems: Edit or create a file in the /etc/audit/rules.d/ directory ending in .rules.
Example: vi /etc/audit/rules.d/50-actions.rules
Add the following lines:
-a exit,always -F arch=b64 -C euid!=uid -F euid=0 -Fauid>=1000 -F auid!=4294967295 -S execve -k actions
-a exit,always -F arch=b32 -C euid!=uid -F euid=0 -Fauid>=1000 -F auid!=4294967295 -S execve -k actions
Default Value
By default, no audit rules are configured for sudo command executions.
References
- CIS Ubuntu Linux 16.04 LTS Benchmark v2.0.0 - Section 4.1.15
CIS Controls
| Controls Version | Control |
|---|---|
| v7 | 4.9 Log and Alert on Unsuccessful Administrative Account Login - Configure systems to issue a log entry and alert on unsuccessful logins to an administrative account. |