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HP-UX ICMP vulnerable to DoS via ICMP Path Maximum Transmission Unit (PMTU) Discovery

Vulnerability Note VU#972686

Original Release Date: 2007-04-12 | Last Revised: 2007-04-12


A vulnerability in HP-UX may allow a remote attacker to cause a denial of service by sending a specially crafted ICMP packet.


A number of widely accepted Internet standards describe different aspects of the relationships between the Internet Control Message Protocol (ICMP) and Transmission Control Protocol (TCP). In particular, RFC 1122 explains how TCP should respond to ICMP messages. Path MTU Discovery (RFC1191) is a method used to discover the maximum transmission unit (MTU) of an arbitrary internet path by using ICMP messages.

HP-UX 11 contains an unspecified vulnerability in how it handles Path MTU Discovery messages. This may allow a remote attacker to cause a denial-of-service condition.


A remote unauthenticated attacker may be able to cause a denial of service by sending a specially crafted ICMP packet to any open TCP/IP connection. The denial of service can only be corrected by a reboot of the affected system.


Apply a patch

Apply a patch, as specified in HP Technical Document c00571568.

Set the PMTU Strategy

Until patches are available, the denial of service may be avoided by setting the ip_pmtu_strategy parameter to 0 or 3, as specified in the HP Security Bulletin.

Vendor Information

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Hewlett-Packard Company

Updated:  April 26, 2005



Vendor Statement

No statement is currently available from the vendor regarding this vulnerability.

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.


Please see the HP Security Bulletin for more details.

If you have feedback, comments, or additional information about this vulnerability, please send us email.

CVSS Metrics

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Thanks to HP for reporting this vulnerability.

This document was written by Will Dormann.

Other Information

CVE IDs: CVE-2005-1192
Severity Metric: 4.05
Date Public: 2005-04-24
Date First Published: 2007-04-12
Date Last Updated: 2007-04-12 16:48 UTC
Document Revision: 10

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