Published:
14 February 2000
Protect yourself against future threats.
-----BEGIN PGP SIGNED MESSAGE----- =========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2000.026 -- REVISED HP SECURITY BULLETIN HPSBUX0001-110 Vulnerability with PMTU strategy 15 February 2000 =========================================================================== Hewlett-Packard has released the following revised bulletin concerning a vulnerability in HP-UX release 10.30, 11.00 and 11.04 only. This vulnerability may be exploited to cause the affected system to flood another system with IP packets which may result in a denial of service. - --------------------------BEGIN INCLUDED TEXT-------------------- Document ID: HPSBUX0001-110 Date Loaded: 20000213 Title: Security Vulnerability with PMTU strategy (revised) - ------------------------------------------------------------------------- **REVISED01**HEWLETT-PACKARD COMPANY SECURITY ADVISORY: #00110, 24 Jan 2000 Last Revised: 11 Feb. 2000 - ------------------------------------------------------------------------- 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: An HP-UX 10.30, 11.00, or 11.04 system can be used as an IP traffic amplifier. Small amounts of inbound traffic can result in larger amounts of outbound traffic. PLATFORM: **REVISED01** - ---->>> HP-UX releases 10.30, 11.00 and 11.04 only. DAMAGE: Depending upon the amount and nature of inbound traffic, an HP-UX 10.30/11.00/11.04 system can be used to flood a target system with IP packets which could result in a denial of service. SOLUTION: Set the NDD parameter ip_pmtu_strategy to 1. AVAILABILITY: This capability is already available. CHANGE SUMMARY: Added HP-UX VirtualVault release 11.04. - ------------------------------------------------------------------------- I. A. Background HP provides a proprietary method for determining PMTU. When traffic needs to be routed to a destination for which the optimum MTU has not been determined, ICMP packets are used to discover the MTU for that path while data traffic is shipped in parallel. This is the default strategy for determining PMTU. B. Recommended solution Reference ndd manpage (1M), /etc/rc.config.d/nddconf To ensure that this parameter is set each time the system is booted, add the following lines to /etc/rc.config.d/nddconf TRANSPORT_NAME[<index>]=ip NDD_NAME[<index>]=ip_pmtu_strategy NDD_VALUE[<index>]=1 The value of <index> is an integer from 0 to 99. The first parameter specified in the file should use an <index> of 0, the second an <index> of 1, and so on. Once these changes have been made, execute the following command: /usr/bin/ndd -c This sets all of the options specified in the file /etc/rc.config.d/nddconf. To verify that the parameter is set correctly, use the following command. /usr/bin/ndd -get /dev/ip ip_pmtu_strategy This should report a value of 1. Another way to change the ip_pmtu_strategy parameter on a running system is to use the following NDD command: /usr/bin/ndd -set /dev/ip ip_pmtu_strategy 1 This setting will only last until the system is rebooted at which point the value of the parameter will be determined by the default value of 2 or whatever value is set in /etc/rc.config.d/nddconf C. To subscribe to automatically receive future NEW HP Security Bulletins from the HP IT Resource Center via electronic mail, do the following: Use your browser to get to the HP IT Resource Center page at: http://us-support.external.hp.com (for US, Canada, Asia-Pacific, & Latin-America) http://europe-support.external.hp.com (for Europe) Under the Maintenance and Support Menu (Electronic Support Center): click on the "more..." link. Then - To -subscribe- to future HP Security Bulletins, or To -review- bulletins already released click on "Support Information Digests" near the bottom of the page, under "Notifications". Login with your user ID and password (or register for one). (Remember to save the User ID assigned to you, and your password). On the "Support Information Digest Main" page: click on the "HP Security Bulletin Archive". Once in the archive the third link is to our current Security Patch Matrix. Updated daily, this matrix categorizes security patches by platform/OS release, and by bulletin topic. The security patch matrix is also available via anonymous ftp: us-ffs.external.hp.com ~ftp/export/patches/hp-ux_patch_matrix E. To report new security vulnerabilities, send email to security-alert@hp.com. Please encrypt any exploit information using the security-alert PGP key, available from your local key server, or by sending a message with a -subject- (not body) of 'get key' (no quotes) to security-alert@hp.com. Permission is granted for copying and circulating this Advisory to Hewlett-Packard (HP) customers (or the Internet community) for the purpose of alerting them to problems, if and only if, the Advisory is not edited or changed in any way, is attributed to HP, and provided such reproduction and/or distribution is performed for non-commercial purposes. Any other use of this information is prohibited. HP is not liable for any misuse of this information by any third party. ________________________________________________________________________ - -----End of Document ID: HPSBUX0001-110-------------------------------------- - --------------------------END INCLUDED TEXT-------------------- This security bulletin is provided as a service to AusCERT's members. As AusCERT did not write the document quoted above, AusCERT has had no control over its content. The decision to use any or all of this information is the responsibility of each user or organisation, and should be done so in accordance with site policies and procedures. NOTE: This is only the original release of the security bulletin. It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the original authors to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: http://www.auscert.org.au/Information/advisories.html If you believe that your system has been compromised, contact AusCERT or your representative in FIRST (Forum of Incident Response and Security Teams). Internet Email: auscert@auscert.org.au Facsimile: (07) 3365 7031 Telephone: (07) 3365 4417 (International: +61 7 3365 4417) AusCERT personnel answer during Queensland business hours which are GMT+10:00 (AEST). On call after hours for emergencies. -----BEGIN PGP SIGNATURE----- Version: 2.6.3i Charset: noconv Comment: ftp://ftp.auscert.org.au/pub/auscert/AUSCERT_PGP.key iQCVAwUBOMy1Pyh9+71yA2DNAQFfvAP9E/Ir+VlkjCpUiJ6JrSNa+odnv5wluxT1 O+bDuQ8AqKpS0OLpDlEo55VR4GDcNWMR3ZbUTJHft/fir7bE5EWyiDCWD076hCmb FmZ4wjXbZEEn1hjc8DyzyPu2AGBodO9m2JgCIlYXc/Yx29z2jdTcQM/gjIyoWhuE zEmiIbNCLnE= =KkMO -----END PGP SIGNATURE-----