Vulnerability Note VU#972686

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

Original Release date: 12 Apr 2007 | Last revised: 12 Apr 2007


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.

Systems Affected (Learn More)

VendorStatusDate NotifiedDate Updated
Hewlett-Packard CompanyAffected-26 Apr 2005
If you are a vendor and your product is affected, let us know.

CVSS Metrics (Learn More)

Group Score Vector
Base N/A N/A
Temporal N/A N/A
Environmental N/A N/A



Thanks to HP for reporting this vulnerability.

This document was written by Will Dormann.

Other Information

  • CVE IDs: CVE-2005-1192
  • Date Public: 24 Apr 2005
  • Date First Published: 12 Apr 2007
  • Date Last Updated: 12 Apr 2007
  • Severity Metric: 4.05
  • Document Revision: 10


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