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The SMTP services SMTP greeting must not provide version information.


Overview

Finding ID Version Rule ID IA Controls Severity
V-220100 GEN004560 SV-220100r603266_rule Low
Description
The version of the SMTP service can be used by attackers to plan an attack based on vulnerabilities present in the specific version.
STIG Date
Solaris 10 X86 Security Technical Implementation Guide 2020-12-04

Details

Check Text ( C-36429r602890_chk )
Check for the Sendmail version being displayed in the greeting.

# telnet localhost 25

If a version number is displayed, this is a finding.

If telnet is unavailable for testing, check the value of the SmtpGreetingMessage parameter in the sendmail.cf file.

# grep SmtpGreetingMessage /etc/mail/sendmail.cf

If the value of the SmtpGreetingMessage parameter contains the $v or $Z macros, this is a finding.
Fix Text (F-36393r602891_fix)
Ensure Sendmail or its equivalent has been configured to mask the version information. If necessary, change the O SmtpGreetingMessage line in the /etc/mail/sendmail.cf file as noted below.
O SmtpGreetingMessage=$j Sendmail $v/$Z; $b
Change it to:
O SmtpGreetingMessage= Mail Server Ready ; $b