Changes are coming to https://stigviewer.com.
Take our survey to help us understand your usage and how we can better serve you in the future.
Take Survey
The SMTP service must not have the EXPN feature active.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
|---|---|---|---|---|
| V-240446 | VRAU-SL-000625 | SV-240446r671079_rule | Medium |
| Description |
|---|
| The SMTP EXPN function allows an attacker to determine if an account exists on a system, providing significant assistance to a brute force attack on user accounts. EXPN may also provide additional information concerning users on the system, such as the full names of account owners. |
| STIG | Date |
|---|---|
| VMware vRealize Automation 7.x SLES Security Technical Implementation Guide | 2023-09-22 |
Details
| Check Text ( C-43679r671077_chk ) |
|---|
| Use the following command to check if EXPN is disabled: # grep -v "^#" /etc/sendmail.cf |grep -i PrivacyOptions If "noexpn" is not returned, this is a finding. |
| Fix Text (F-43638r671078_fix) |
|---|
| Add "noexpn" to the "PrivacyOptions" flag in /etc/sendmail.cf |