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Cisco ACNS RealServer RealSubscruber vulnerable to DoS via malformed IP packets

Vulnerability Note VU#579240

Original Release Date: 2005-03-10 | Last Revised: 2005-03-10


A vulnerability in Cisco ACNS RealServer RealSubscriber may allow a remote attacker to cause a denial of service on an affected device via malformed IP packets.


Cisco Application and Content Networking System (ACNS) is an integrated caching and content-delivery platform. ACNS 5.1 includes RealServer as an optional component. RealSubscriber is RealServer configured for subscriber-only mode. RealSubscriber is disabled by default. Specially crafted packets may cause RealSubscriber to consume 100% of the CPU of an affected device. A reboot of the device is required to recover.


A remote, unauthenticated attacker could cause a denial-of-service condition on an affected system.


Apply a patch or upgrade

Please refer to the "Software Versions and Fixes" section of the Cisco Security Advisory for more information on upgrading.

Disable RealSubscriber

Please see the "Workarounds" section of the Cisco Security Advisory for information about how to disable RealSubscriber.

Restrict access

Use Access Control Lists (ACLs) to block or restrict access to affected devices from untrusted networks. Please see the "Workarounds" section of the Cisco Security Advisory.

Vendor Information


Cisco Systems Inc. Affected

Updated:  February 28, 2005



Vendor Statement

We have not received a statement from the vendor.

Vendor Information

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


Please see the Cisco Security Advisory.

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

CVSS Metrics

Group Score Vector



This vulnerability was reported by the Cisco Systems Product Security Incident Response Team (PSIRT).

This document was written by Will Dormann.

Other Information

CVE IDs: CVE-2005-0598
Severity Metric: 3.47
Date Public: 2005-02-24
Date First Published: 2005-03-10
Date Last Updated: 2005-03-10 22:00 UTC
Document Revision: 7

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