cyberstrikeus CIS Ubuntu Linux 18.04 LTS Benchmark v2.2.0 - Control 4.2.15
Profile Applicability
- Level 1 - Server
- Level 1 - Workstation
Description
The MaxAuthTries parameter specifies the maximum number of authentication attempts permitted per connection. When the login failure count reaches half the number, error messages will be written to the syslog file detailing the login failure.
Rationale
Setting the MaxAuthTries parameter to a low number will minimize the risk of successful brute force attacks to the SSH server. While the recommended setting is 4, set the number based on site policy.
Audit Procedure
Command Line
Run the following command and verify the output:
sshd -T | grep -i maxauthtries
Expected Result
maxauthtries 4
Value should be 4 or less.
Remediation
Command Line
Edit the /etc/ssh/sshd_config file to set the parameter as follows:
MaxAuthTries 4
Default Value
MaxAuthTries 6
References
- NIST SP 800-53 Rev. 5: AU-3, AU-12
CIS Controls
v8 - 8.5 Collect Detailed Audit Logs - Configure detailed audit logging for enterprise assets containing sensitive data.
v7 - 16.13 Alert on Account Login Behavior Deviation.
Profile Applicability
- Level 1 - Server
- Level 1 - Workstation
Assessment Status
Automated