MTA Open Mail Relaying Allowed (internal)

high Nessus Plugin ID 118017
New! Plugin Severity Now Using CVSS v3

The calculated severity for Plugins has been updated to use CVSS v3 by default. Plugins that do not have a CVSS v3 score will fall back to CVSS v2 for calculating severity. Severity display preferences can be toggled in the settings dropdown.


An open SMTP relay is running on the host.


Nessus has detected that this internal SMTP server allows mail relaying.


Reconfigure your SMTP server so that it cannot be used as an indiscriminate SMTP relay. Make sure that the server uses appropriate access controls to limit the extent to which relaying is possible.

See Also

Plugin Details

Severity: High

ID: 118017

File Name: internal_smtp_relay_detection.nasl

Version: 1.4

Type: remote

Published: 10/10/2018

Updated: 6/1/2020

Dependencies: smtpserver_detect.nasl, sendmail_expn.nasl, smtp_settings.nasl

Configuration: Enable paranoid mode

Risk Information

CVSS Score Source: manual

CVSS Score Rationale: Score from a more in depth analysis done by tenable


Risk Factor: Medium

Score: 5.9


Risk Factor: High

Base Score: 7.8

Temporal Score: 6.6

Vector: AV:N/AC:L/Au:N/C:N/I:N/A:C

Temporal Vector: E:U/RL:ND/RC:C


Risk Factor: High

Base Score: 7.5

Temporal Score: 6.9

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: E:U/RL:X/RC:C

Vulnerability Information

Required KB Items: Settings/ParanoidReport

Excluded KB Items: SMTP/wrapped, SMTP/qmail

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 1/1/1990

Reference Information

CVE: CVE-1999-0512, CVE-2002-1278, CVE-2003-0285

BID: 7580, 8196, 83209