[security bulletin] SSRT4884 HP-UX TCP/IP Remote Denial of Service (DoS)
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SUPPORT COMMUNICATION - SECURITY BULLETIN
Document ID: c00576017
Version: 8
HPSBUX01164 SSRT4884 HP-UX TCP/IP Remote Denial of Service (DoS)
NOTICE: The information in this Security Bulletin should be acted
upon as soon as possible.
Release Date: 2005-05-25
Last Updated: 2005-12-06
Potential Security Impact: Remote Denial of Service (DoS)
Source: Hewlett-Packard Company,
HP Software Security Response Team
VULNERABILITY SUMMARY
A potential security vulnerability has been identified with HP-UX
running TCP/IP. This vulnerability could be remotely exploited by
an unauthorized user to cause a Denial of Service(DoS).
References: NISCC VU#532967, CAN-2004-0790, CAN-2004-0791,
CAN-2004-1060
SUPPORTED SOFTWARE VERSIONS*: ONLY impacted versions are listed.
HP-UX B.11.00, B.11.04, B.11.11, B.11.22, B.11.23 running TCP/IP.
HP-UX B.11.11 and B.11.23 running TOUR (Transport Optional Upgrade
Release).
BACKGROUND
As reported in NISCC VU#532967:
http://www.uniras.gov.uk/niscc/docs/al-20050412-00308.html?lang=en
ICMP messages may be used to attack TCP/IP connections.
There are three issues reported in NISCC VU#532967:
CVE number: CAN-2004-0790
http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2004-0790
CVE number: CAN-2004-0791
http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2004-0791
CVE number: CAN-2004-1060
http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2004-1060
AFFECTED VERSIONS
HP-UX B.11.00
=============
Networking.NET2-KRN
action: install PHNE_33395, optionally set ip_pmtu_strategy=0
HP-UX B.11.04
=============
Networking.NET2-KRN
action: install PHNE_33427, optionally set ip_pmtu_strategy=0
HP-UX B.11.11
=============
Networking.NET2-KRN
action: install PHNE_33159, optionally set ip_pmtu_strategy=0
HP-UX B.11.22
=============
Networking.NET2-KRN
action: install binary files, optionally set ip_pmtu_strategy=0
HP-UX B.11.23
=============
Networking.NET2-KRN
action: install PHNE_32606, optionally set ip_pmtu_strategy=0
HP-UX B.11.11
HP-UX B.11.23
=============
TOUR_PRODUCT.T-NET2-KRN
->action: install revision A.03.00, optionally set
ip_pmtu_strategy=0
END AFFECTED VERSIONS
RESOLUTION
HP has made the following patches, updates, and binary
files available to resolve the issue.
Patches are available for the core network product from
http://itrc.hp.com :
B.11.00 PHNE_33395 or subsequent
B.11.04 PHNE_33427 or subsequent
B.11.11 PHNE_33159 or subsequent
B.11.23 PHNE_32606 or subsequent
->TOUR revision 3.0 is available from:
->http://www.hp.com/go/softwaredepot
->Binary files are available for B.11.22. Please write to
->security-alert@xxxxxx for more information.
Optionally set ip_pmtu_strategy=0 to work around CAN-2004-1060.
However, this may not be necessary:
Although changes in the binary files and patches for CAN-2004-0790
and CAN-2004-0791 do not prevent the exploit of CAN-2004-1060,
they do make it less likely to succeed. The sequence number check
suggested in section 5.1 of 'ICMP attacks against TCP' has been
implemented. The Internet Draft of 'ICMP attacks against TCP' can
be found here:
http://www.gont.com.ar/drafts/icmp-attacks-against-tcp.html
Customers should consider whether this check reduces the risk of
the exploit to the point that setting ip_pmtu_strategy=0 is not
required.
Note: ip_pmtu_strategy=0 sets the PMTU to 576 bytes and clears the
"Don't Fragment" bit. This disables PMTU discovery. For IPv4 the
Next-Hop MTU may be as low as 68 bytes. Therefore setting
ip_pmtu_strategy=0 may cause performance to decrease.
To set ip_pmtu_strategy=0:
Edit /etc/rc.config.d/nddconf to add the following:
TRANSPORT_NAME[n]=ip
NDD_NAME[n]=ip_pmtu_strategy
NDD_VALUE[n]=0
where 'n' is the next available index value as described in the
nddconf comments.
This value will take effect when the system is rebooted.
Until the system can be rebooted use the following command to read
the /etc/rc.config.d/nddconf file and set the tunable parameters:
/usr/bin/ndd -c
The ip_pmtu_strategy parameter can be displayed by the following
command:
/usr/bin/ndd -get /dev/ip ip_pmtu_strategy
Note: Since open connections will remain potentially vulnerable
until they are closed and certain internal data structures are
released it is recommended that the system be rebooted.
Note: There is a defect that will cause "ndd -c" to fail if there
are more than 10 directives in /etc/rc.config.d/nddconf. That
defect is fixed in the following patches:
B.11.11 PHNE_25644 or subsequent
B.11.04 PHNE_26076 or subsequent
B.11.00 PHNE_26125 or subsequent
MANUAL ACTIONS: Yes - NonUpdate
Optionally set ip_pmtu_strategy=0
PRODUCT SPECIFIC INFORMATION
HP-UX Security Patch Check: Security Patch Check revision B.02.00
analyzes all HP-issued Security Bulletins to provide a subset of
recommended actions that potentially affect a specific HP-UX
system. For more information:
http://software.hp.com/portal/swdepot/displayProductInfo.do?
productNumber=B6834AA
UPDATE HISTORY
Initial release: 25 May 2005
Update 1: 1 June 2005 Binary files for B.11.00 and B.11.22 are
available.
Update 2: 19 June 2005 Added TOUR information.
Update 3: 27 June 2005 PHNE_33159 is available for B.11.11.
Update 4: 10 July 2005 PHNE_32606 is available for B.11.23.
Update 5: 24 July 2005 PHNE_33395 is available for B.11.00.
Update 6: 15 August 2005 PHNE_33427 is available for B.11.04.
Support: For further information, contact normal HP Services
support channel.
Report: To report a potential security vulnerability with any HP
supported product, send Email to: security-alert@xxxxxxx It is
strongly recommended that security related information being
communicated to HP be encrypted using PGP, especially exploit
information. To get the security-alert PGP key, please send an
e-mail message as follows:
To: security-alert@xxxxxx
Subject: get key
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* The Software Product Category that this Security Bulletin
relates to is represented by the 5th and 6th characters of the
Bulletin number in the title:
GN = HP General SW,
MA = HP Management Agents,
MI = Misc. 3rd party SW,
MP = HP MPE/iX,
NS = HP NonStop Servers,
OV = HP OpenVMS,
PI = HP Printing & Imaging,
ST = HP Storage SW,
TL = HP Trusted Linux,
TU = HP Tru64 UNIX,
UX = HP-UX,
VV = HP Virtual Vault
System management and security procedures must be reviewed
frequently to maintain system integrity. HP is continually
reviewing and enhancing the security features of software products
to provide customers with current secure solutions.
"HP is broadly distributing this Security Bulletin in order to
bring to the attention of users of the affected HP products the
important security information contained in this Bulletin. HP
recommends that all users determine the applicability of this
information to their individual situations and take appropriate
action. HP does not warrant that this information is necessarily
accurate or complete for all user situations and, consequently, HP
will not be responsible for any damages resulting from user's use
or disregard of the information provided in this Bulletin. To the
extent permitted by law, HP disclaims all warranties, either
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(c)Copyright 2005 Hewlett-Packard Development Company, L.P.
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products referenced herein are trademarks of Hewlett-Packard
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