Check: GEN004660
HP-UX 11.31 STIG:
GEN004660
(in versions v1 r19 through v1 r13)
Title
The SMTP service must not have the EXPN feature active. (Cat III impact)
Discussion
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.
Check Content
Perform the following to determine if EXPN is disabled: # telnet localhost 25 expn root If the command does not return a 500 error code (command unrecognized), this is a finding. OR Check the sendmail.cf configuration file by: # cat /etc/mail/sendmail.cf | tr '\011' ' ' | tr -s ' ' | sed -e 's/^[ \t]*//' | grep -v "^#" |\ grep -i privacyoptions | egrep -c -i "noexpn|goaway" The O PrivacyOptions should have the noexpn or the goaway option (covering both noexpn and novrfy). If the EXPN command is not disabled, this is a finding.
Fix Text
Edit the /etc/mail/sendmail.cf file and add or edit the following line: O PrivacyOptions=goaway Then restart the Sendmail service.
Additional Identifiers
Rule ID: SV-35076r1_rule
Vulnerability ID: V-4692
Group Title: GEN004660
Expert Comments
CCIs
Number | Definition |
---|---|
CCI-000366 |
The organization implements the security configuration settings. |
Controls
Number | Title |
---|---|
CM-6 |
Configuration Settings |