TUCoPS :: Unix :: General :: m-054.txt

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 The U.S. Department of Energy
 Computer Incident Advisory Center
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 INFORMATION BULLETIN
 OpenSSH Contains Remotely Exploitable Vulnerability
 [Pine Internet Security Advisory 20020301]
March 7, 2002 18:00 GMT Number M-054
______________________________________________________________________________
PROBLEM: A remotely exploitable vulnerability has been identified in the 
 channel code of OpenSSH. 
PLATFORM: All platforms using OpenSSH versions prior to version 3.1. 
DAMAGE: Users with an existing account could upgrade privileges, up to 
 and including root. Exploitability without an existing user 
 account has not been proven but is not considered impossible. A 
 malicious ssh server could also use this vulnerability to 
 exploit a connecting vulnerable client. 
SOLUTION: CIAC recommends that you upgrade to version 3.1 or apply the 
 included patch. 
______________________________________________________________________________
VULNERABILITY The risk is MEDIUM. Exploitability without an existing user 
ASSESSMENT: account has not been proven. 
______________________________________________________________________________
LINKS: 
 CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/m-054.shtml 
 ORIGINAL BULLETIN: http://www.pine.nl/advisories/pine-cert-20020301.txt 
 PATCHES: http://www.openssh.com 
 http://www.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh 
 http://www.pine.nl/advisories/pine-cert-20020301.patch 
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[***** Start Pine Internet Security Advisory 20020301 *****]
-----------------------------------------------------------------------------
 Pine Internet Security Advisory
-----------------------------------------------------------------------------
 Advisory ID : PINE-CERT-20020301
 Authors : Joost Pol <joost@pine.nl>
 Issue date : 2002年03月07日
 Application : OpenSSH
 Version(s) : All versions between 2.0 and 3.0.2
 Platforms : multiple
 Vendor informed : 20020304
 Availability : http://www.pine.nl/advisories/pine-cert-20020301.txt
-----------------------------------------------------------------------------
Synopsis
 A bug exists in the channel code of OpenSSH versions 2.0 - 3.0.2
 Users with an existing user account can abuse this bug to
 gain root privileges. Exploitability without an existing
 user account has not been proven but is not considered
 impossible. A malicious ssh server could also use this bug 
 to exploit a connecting vulnerable client.
Impact
 HIGH: Existing users will gain root privileges.
Description
 Simple off by one error. Patch included.
Solution
 The OpenSSH project will shortly release version 3.1. 
	
 Upgrading to this version is highly recommended. 
 This version will be made available at http://www.openssh.com
 The FreeBSD port of OpenSSH has been updated to reflect the 
 patches as supplied in this document.
 OpenSSH CVS has been updated, see:
 
 OpenBSD cvs entry for channels.c at
 http://www.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/channels.c.diff?r1=1.170&r2=1.171
 Or apply the attached patch as provided by PINE Internet:
 http://www.pine.nl/advisories/pine-cert-20020301.patch
[***** End Pine Internet Security Advisory 20020301 *****]
_______________________________________________________________________________
CIAC wishes to acknowledge the contributions of Pine CERT for the 
information contained in this bulletin.
_______________________________________________________________________________
CIAC, the Computer Incident Advisory Center, is the computer
security incident response team for the U.S. Department of Energy
(DOE) and the emergency backup response team for the National
Institutes of Health (NIH). CIAC is located at the Lawrence Livermore
National Laboratory in Livermore, California. CIAC is also a founding
member of FIRST, the Forum of Incident Response and Security Teams, a
global organization established to foster cooperation and coordination
among computer security teams worldwide.
CIAC services are available to DOE, DOE contractors, and the NIH. CIAC
can be contacted at:
 Voice: +1 925-422-8193 (7x24)
 FAX: +1 925-423-8002
 STU-III: +1 925-423-2604
 E-mail: ciac@ciac.org
Previous CIAC notices, anti-virus software, and other information are
available from the CIAC Computer Security Archive.
 World Wide Web: http://www.ciac.org/
 Anonymous FTP: ftp.ciac.org
PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing
communities receive CIAC bulletins. If you are not part of these
communities, please contact your agency's response team to report
incidents. Your agency's team will coordinate with CIAC. The Forum of
Incident Response and Security Teams (FIRST) is a world-wide
organization. A list of FIRST member organizations and their
constituencies can be obtained via WWW at http://www.first.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
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otherwise, does not necessarily constitute or imply its endorsement,
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University of California. The views and opinions of authors expressed
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Government or the University of California, and shall not be used for
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