Xinetd TCPMUX Bug Lets Remote Users Access Restricted Services
SecurityTracker Alert ID: 1027050|
SecurityTracker URL: http://securitytracker.com/id/1027050
(Links to External Site)
Date: May 9 2012
Host/resource access via network|
Fix Available: Yes Vendor Confirmed: Yes |
Version(s): prior to 2.3.15|
A vulnerability was reported in Xinetd. A remote user can access restricted services.|
If the tcpmux-server service is enabled, a remote user can connect to the tcpmux port to access all enabled services instead of just the configured services.
Thomas Swan of FedEx reported this vulnerability.
A remote user can access restricted services.|
The vendor has issued a fix (2.3.15)|
The vendor's advisory is available at:
Vendor URL: www.xinetd.org/ (Links to External Site)
Access control error|
|Underlying OS: Linux (Any)|
This archive entry has one or more follow-up message(s) listed below.|
Source Message Contents
Subject: [oss-security] CVE-2012-0862 assignment notification: xinetd enables unintentional services over tcpmux port|
Thomas Swan of FedEx reported a service disclosure flaw in xinetd.
xinetd allows for services to be configured with the TCPMUX or
TCPMUXPLUS service types, which makes those services available on port
1, as per RFC 1078 , if the tcpmux-server service is enabled. When
the tcpmux-server service is enabled, xinetd would expose _all_ enabled
services via the tcpmux port, instead of just the configured service(s).
This could allow a remote attacker to bypass firewall restrictions and
access services via the tcpmux port.
In order for enabled services handled by xinetd to be exposed via the
tcpmux port, the tcpmux-server service must be enabled (by default it is
This has been assigned CVE-2012-0862.
Thomas Swan also provided a patch , which has been reviewed by a
former xinetd upstream maintainer and the Red Hat xinetd maintainer
(upstream didn't respond to our contact attempts).
-- References --
 Red Hat bug:
 Proposed patch:
Thanks and kind regards,
Stefan Cornelius / Red Hat Security Response Team