Privacy and Legal Notice

CIAC INFORMATION BULLETIN

R-139: Security Vulnerability in the in.telnetd(1M) Daemon

[Sun Alert ID: 102802]

February 14, 2007 16:00 GMT
[REVISED 22 Feb 2007]
PROBLEM: A security vulnerability in the in.telnetd(1M) daemon shipped with Solaris 10.
PLATFORM: SPARC Platform
  Solaris 10 without patch 120068-02

x86 Platform
  Solaris 10 without patch 120069-02
DAMAGE: May allow a local or remote unprivileged user who is able to connect to a host using the telnet(1) service to gain unauthorized access to that host by connecting as any user on the system, allowing them to execute arbitrary commands with the privileges of that user.
SOLUTION: Upgrade to the appropriate version.
VULNERABILITY
ASSESSMENT:		 The risk is MEDIUM. A remote unprivileged user who can login to a system using telnet can get root access.
LINKS:  
  CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/r-139.shtml
  ORIGINAL BULLETIN: http://www.sunsolve.sun.com/search/document.do?assetkey=1-26-102802-1
  CVE: CVE-2007-0882 
REVISION HISTORY:
	02/22/2007 - revised R-139 to reflect changes Sun has made in Sun Alert ID: 102802
                 where they Updated the Resolution section.
				 
				 
				 
[***** Start Sun Alert ID: 102802 *****]
Sun(sm) Alert Notification

1. Impact

A security vulnerability in the in.telnetd(1M) daemon shipped with Solaris 10 may allow a local or remote unprivileged user who is able to connect to a host using the telnet(1) service to gain unauthorized access to that host by connecting as any user on the system, allowing them to execute arbitrary commands with the privileges of that user. This would include the root user (uid 0) if the host is configured to accept telnet logins as the root user.

This issue is described in the following documents:

CERT VU#881872 at http://www.kb.cert.org/vuls/id/881872

CVE-2007-0882 at http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-0882

2. Contributing Factors

This issue can occur in the following releases:

SPARC Platform

  • Solaris 10 without patch 120068-02

x86 Platform

  • Solaris 10 without patch 120069-02

Notes:

  1. Solaris 8 and 9 are not affected by this issue.
  2. This issue only affects systems which have the telnet(1) service enabled.

The following command can be used to determine if the service is enabled, which will output 'online' for the service state if the system is affected by this issue:

    $ svcs telnet
    STATE          STIME    FMRI
    online         Jan_30   svc:/network/telnet:default

If remote root logins are disabled, the impact of this issue will be limited to users other than root.

Remote root logins are disabled if the file "/etc/default/login" contains a line that begins with 'CONSOLE'. This can be seen using the grep command as shown below:

    $ grep CONSOLE /etc/default/login
    CONSOLE=/dev/console

If this line has been commented out by inserting a '#' at the beginning, as in the following example:

    #CONSOLE=/dev/console

or if there is no line containing the word 'CONSOLE', then this issue will also apply to the root user.

See login(1) for more information about the /etc/default/login file.

3. Symptoms

Depending on the manner in which this issue has been exploited, the output from commands such as last(1) (which display information about login and logout activity), may show unexpected logins to the system. Using the '-a' flag with the last(1) command will show the hostname associated with these logins.


Solution Summary Top

4. Relief/Workaround

To workaround this issue, the telnet service can be disabled as in the following example (Note that this will remove the functionality of the in.telnetd daemon on that host):

    # svcadm disable svc:/network/telnet:default

Note: If instead of disabling the service, removal of the service is being considered, then please first read Sun Alert 102799:

"Synopsis: svc.startd(1M) May Core Dump While Removing a Service, Causing patchrm(1M) to Terminate and Leave the System Unbootable"

In addition, it is also possible to uncomment (or add) the 'CONSOLE' line in the "/etc/default/login" file so that it looks similar to the following:

    CONSOLE=/dev/console

However, this will only prevent unauthorized access to the root account; other user accounts will still be affected by this issue.


5. Resolution

This issue is addressed in the following releases:

SPARC Platform

  • Solaris 10 with patch 120068-02 or later

x86 Platform

  • Solaris 10 with patch 120069-02 or later

 

Note: These patches have been created with a tag that says that a reboot is required after installation. However, this is incorrect (see Bug 6524404). Future Solaris 10 telnetd(1M) patch revisions have had this tag removed.


Change History

13-Feb-2007:
  • Updated Contributing Factors and Resolution sections
  • State: Resolved
14-Feb-2007:
  • Updated Relief/Workaround section

This Sun Alert notification is being provided to you on an "AS IS" basis. This Sun Alert notification may contain information provided by third parties. The issues described in this Sun Alert notification may or may not impact your system(s). Sun makes no representations, warranties, or guarantees as to the information contained herein. ANY AND ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT, ARE HEREBY DISCLAIMED. BY ACCESSING THIS DOCUMENT YOU ACKNOWLEDGE THAT SUN SHALL IN NO EVENT BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES THAT ARISE OUT OF YOUR USE OR FAILURE TO USE THE INFORMATION CONTAINED HEREIN. This Sun Alert notification contains Sun proprietary and confidential information. It is being provided to you pursuant to the provisions of your agreement to purchase services from Sun, or, if you do not have such an agreement, the Sun.com Terms of Use. This Sun Alert notification may only be used for the purposes contemplated by these agreements.

Copyright 2000-2006 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, CA 95054 U.S.A. All rights reserved.




[***** End Sun Alert ID: 102802 *****]
CIAC wishes to acknowledge the contributions of Sun Microsystems for the information contained in this bulletin.
CIAC services are available to DOE, DOE Contractors, and the NIH. CIAC can be contacted at: 
    Voice:          +1 925-422-8193 (7 x 24)
    FAX:            +1 925-423-8002
    STU-III:        +1 925-423-2604
    E-mail:          ciac@ciac.org
    World Wide Web:  http://www.ciac.org/
    Anonymous FTP:   ftp.ciac.org
This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation or favoring by the United States Government or the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or the University of California, and shall not be used for advertising or product endorsement purposes.
UCRL-MI-119788
[Privacy and Legal Notice]