Cisco Security Advisory
Cisco Intrusion Prevention System Malformed Packet Denial of Service
-
Cisco Intrusion Prevention System (IPS) software version 5.1 is vulnerable to a denial of service condition caused by a malformed packet, which may result in an IPS device becoming inaccessible remotely or via the console and fail to process packets. A power reset is required to recover the IPS device. There are no workarounds for this vulnerability.
Cisco has made free software available to address this vulnerability for affected customers.
This advisory is posted at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20060712-ips.
-
This section provides details on affected products.
Vulnerable Products
Cisco Intrusion Prevention System 42xx appliances running IPS software versions 5.1(1), 5.1(1a), 5.1(1b), 5.1(1c), 5.1(1d), 5.1(1e) or 5.1(p1).
IPS software versions 5.1(1a), 5.1(1b), 5.1(1c), 5.1(1d) and 5.1(1e) are repackaged versions of 5.1(1) created to fix various installation problems. All 5.1(1) patch versions report 5.1(1) as the installed version.
Note: Some IDS/IPS appliances shipped before IPS software version 5.0 was available and have model numbers starting with IDS, not IPS.
The following 42xx appliances are potentially affected.
-
IDS-4235
-
IPS-4240
-
IDS-4250-SX
-
IDS-4250-TX
-
IDS-4250-XL (4250 with XL accelerator card)
-
IPS-4255
Products Confirmed Not Vulnerable
All devices running Cisco Intrusion Detection Systems (IDS) software versions 4.x or IPS versions 5.0(x).
Additionally, the following devices are not vulnerable even if running IPS software versions 5.1(1), 5.1(1a), 5.1(1b), 5.1(1c), 5.1(1d), 5.1(1e) or 5.1(1p1).
-
NM-CIDS
-
IDSM-2
-
ASA-SSM-AIP-10
-
ASA-SSM-AIP-20
-
IDS-4210
-
IDS-4215
The following devices do not support IPS software version 5.1 and are not vulnerable.
-
IDS-4220
-
IDS-4230
To determine the version of software running an IPS device, log into the IPS device using an SSH client and issue the command show version.
sensor#show version Application Partition: Cisco Intrusion Prevention System, Version 5.1(1p1)S215.0
-
IDS-4235
-
Cisco Intrusion Prevention Systems (IPS) are a family of network security devices that provide network based threat prevention services. A vulnerability exists in the custom device driver for Intel-based gigabit network adapters used to process packets received by the sensing interfaces of certain IPS devices. A malformed IP packet received on an Intel-based gigabit network adapter configured for use as a sensing interface may result in the IPS device experiencing a kernel panic. Affected IPS devices will cease processing packets, producing alerts, performing automated actions such as logging, and become inaccessible remotely or via the console.
If deployed as an inline device, the IPS will also stop forwarding packets between interfaces and may cause a network outage. IPS devices configured to use the auto-bypass feature will also fail to forward packets. Attackers may use this vulnerability to disable an IPS device to hide malicious activity. This vulnerability only affects certain IPS devices configured to use Intel-based gigabit network adapters as sensing interfaces. IPS devices configured to use an Intel-based gigabit network adapter as a management interface are not affected by this vulnerability. A power reset is required to recover the IPS device.
This vulnerability is documented in Cisco bug ID CSCsd36590 ( registered customers only) .
-
There are no workarounds for this vulnerability.
-
When considering software upgrades, also consult http://www.cisco.com/go/psirt and any subsequent advisories to determine exposure and a complete upgrade solution.
In all cases, customers should exercise caution to be certain the devices to be upgraded contain sufficient memory and that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, contact the Cisco Technical Assistance Center ("TAC") or your contracted maintenance provider for assistance.
This issue is fixed in IPS version 5.1(2) which is available for download at http://www.cisco.com/pcgi-bin/tablebuild.pl/ips5 ( registered customers only) .
-
The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability described in this advisory.
-
To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
-
THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS DOCUMENT AT ANY TIME.
A stand-alone copy or paraphrase of the text of this document that omits the distribution URL is an uncontrolled copy, and may lack important information or contain factual errors. The information in this document is intended for end-users of Cisco products.