X-RDate: Thu, 12 Feb 1998 18:23:30 +0500 (ESK)
Date: Wed, 11 Feb 1998 08:29:51 -0500
From: [email protected]
To: [email protected]Subject: IBM-ERS Security Vulnerability Alert: IBM AIX: Telnet denial of service attack
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EMERGENCY RESPONSE SERVICE
SECURITY VULNERABILITY ALERT
11 February 1998 13:30 GMT Number: ERS-SVA-E01-1998:003.1
VULNERABILITY SUMMARY
VULNERABILITY: Telnet denial of service attack
PLATFORMS: IBM AIX(r) 4.1.x, 4.2.x, 4.3
SOLUTION: Apply the fixes listed below.
THREAT: Remote users can cause the system to hang.
DETAILED INFORMATION
I. Description
A denial of service attack has been posted to the Bugtraq mailing list
that causes all tty activity to hang and prevents new telnet sessions
from being established.
II. Impact
Remote users can cause the system to run out of message blocks and
hang.
III. Solutions
A. Official fix
At this time, only the AIX 4.1.x APAR is available. AIX 4.2.x
and 4.3.0 customers can apply the temporary fix listed below
until the official APARs are available. There are no fixes
planned for AIX 3.2.5 or earlier. It is recommended that version
3 customers upgrade to version 4.
AIX 4.1.x: IX73427 (bos.rte.tty 4.1.5.20) -- available now
AIX 4.2.x: IX73580
AIX 4.3.0: IX73214
B. How to alleviate the problem
A temporary fix is available for AIX 4.2.x and AIX 4.3.0 via
anonymous ftp from:
ftp://aix.software.ibm.com/aix/efixes/security/ldterm_fix.tar.Z
Filename sum md5
ldterm.42 52419 77 7ec3ff7eb83ded8f50219a838a0a4c0b
ldterm.43 37579 77 f066b7d6c3a845c892941a7ab15a6e60
ldterm_fix.sh 10210 3 e3a8bbecda52ff68391657f008b46262
Use the following steps (as root) to install the temporary fix:
1. Use the following command to determine the version of the
bos.rte.tty fileset on your machine.
# lslpp -l bos.rte.tty
If the version is not at the level described below, install
the requisite APAR for your release. This will help ensure
that the efix binary will run properly.
Release bos.rte.tty version requisite APAR
AIX 4.2.x less than 4.2.1.9 install IX73755
AIX 4.3.0 less than 4.3.0.3 install IX73397
2. Uncompress and extract the fix.
# uncompress < ldterm_fix.tar.Z | tar xf -
# cd ldterm_fix
3. Run the ldterm_fix.sh script to install the new tty driver.
# ./ldterm_fix.sh
4. Reboot.
NOTE: This temporary fix has not been fully regression tested.
IV. Obtaining Fixes
IBM AIX APARs may be ordered using Electronic Fix Distribution (via the
FixDist program), or from the IBM Support Center. For more information
on FixDist, and to obtain fixes via the Internet, please reference
http://service.software.ibm.com/aixsupport/
or send electronic mail to "[email protected]" with the word
"FixDist" in the "Subject:" line.
V. Acknowledgements
Thanks to Kevin Ruderman <rudi@bu.edu.> for bringing this problem to our
attention.
VI. Contact Information
Comments regarding the content of this announcement can be directed to
the IBM Support Center or to:
[email protected]
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Copyright 1998 International Business Machines Corporation.
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