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[HP] Schwachstelle in xntpd - HPSBUX0104-148
[[PGP Signed Part:Undecided]]
Liebe Kolleginnen und Kollegen,
soeben erreichte uns das nachfolgende Bulletin der HP SupportLine.
Wir geben diese Informationen unveraendert an Sie weiter.
Beschrieben wird ein Buffer Overflow im Network Time Daemon (xntpd)
durch die ein Angreifer ueber das Netz beliebigen Code mit
Root-Rechten auf dem betroffenen Rechner ausfuehren kann, indem er/sie
ein entsprechend formuliertes NTP-Paket an den xntpd Prozess sendet.
Betroffen von dieser Schwachstelle sind HP-UX 10.xx und 11.xx. Derzeit
steht noch kein Patch bereit, HP empfiehlt jedoch als Workaround mit
Hilfe der Restrict Anweisungen in /etc/ntp.conf den Zugriff vom Netz
auf den xntpd-Prozess so weit wie moeglich einzuschraenken. Details
entnehmen Sie bitte dem angefuegten Advisory bzw. der xntpd
Dokumentation.
Wie ueblich, ist das Advisory von HP nicht digital signiert.
Mit freundlichen Gruessen,
Klaus Moeller, DFN-CERT
--
Klaus Moeller | mailto:moeller@cert.dfn.de
DFN-CERT GmbH | http://www.cert.dfn.de/team/moeller/
Oberstrasse 14b | Phone: +49(40)808077-555
D-20144 Hamburg | FAX: +49(40)808077-556
Germany | PGP-Key: finger moeller@ftp.cert.dfn.de
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Digest Name: daily security bulletins digest
Created: Mon Apr 9 5:40:03 PDT 2001
Table of Contents:
Document ID Title
--------------- -----------
HPSBUX0104-148 Sec. Vulnerability in xntpd(1M)
The documents are listed below.
-------------------------------------------------------------------------------
Document ID: HPSBUX0104-148
Date Loaded: 20010407
Title: Sec. Vulnerability in xntpd(1M)
-------------------------------------------------------------------------
HEWLETT-PACKARD COMPANY SECURITY ADVISORY: #0148, 06 Apr. '01
-------------------------------------------------------------------------
The information in the following Security Advisory should be acted upon
as soon as possible. Hewlett-Packard Company will not be liable for any
consequences to any customer resulting from customer's failure to fully
implement instructions in this Security Advisory as soon as possible.
-------------------------------------------------------------------------
PROBLEM: The HP-UX NTP daemon contains an exploitable vulnerability.
PLATFORM: HP9000 Series 700/800 running HP-UX releases 10.XX and 11.XX.
DAMAGE: Possible denial of service, increase of priviledge.
SOLUTION: Install the workaround configuration detailed below.
AVAILABILITY: Patches are currently being developed, whereupon this
advisory will be upgraded to a bulletin.
-------------------------------------------------------------------------
I.
A. Background
A buffer overflow has been discovered on various Unix-derived
operating systems in its NTP daemon. Hewlett-Packard Company
ships xntpd on HP-UX releases and has determined that it too,
is vulnerable.
B. Recommended solution
Hewlett-Packard Company recommends that xntpd be shut down
on all systems not absolutely needing time-of-day synchronization
with Internet standard time servers.
On those remaining time-sensitive systems modify the default
configuration file (/etc/ntp.conf) to use the "restrict" clause,
to restrict all but allow some.
We provide an example of a simple configuration. Please refer
to the man (1M) xntpd for further configuration details.
# This server syncs from server 192.255.2.3 and provides
# time services to client 192.27.16.30, yet
# blocks all others.
server 192.255.2.3 prefer
server 127.127.1.1
# allow this client full access
restrict 192.27.16.30
# allow this server full access
restrict 192.255.2.3
# you need both of the following for the localhost
restrict 127.0.0.1
restrict 127.127.1.1
# block everything else
restrict default ignore
NOTE: Patches are currently in development.
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________________________________________________________________________
-----End of Document ID: HPSBUX0104-148--------------------------------------
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