Cisco Security Advisory-
A software bug (Cisco bug ID CSCdi74333) allows remote TCP/IP users to cause reloads of Cisco Catalyst LAN switches running Catalyst 5000 supervisor software versions from 1.0 through 2.1(5). The affected software was last shipped with new units in early 1997. In addition to the Catalyst 5xxx series, some, but not all, Catalyst 29xx family switches may run the affected software; see "Who is Affected" for more information.
A similar bug, Cisco bug ID CSCdj71684, exists in the supervisor software for the older, and now discontinued, Catalyst 12xx family, up through software version 4.29.
Fixes are available for both bugs. The fixes have been in the field for some time. Most Catalyst switch users have probably already installed the fixes.
This advisory is posted at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-19990324-cat7161.
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This section provides details on affected products.
Vulnerable Products
The following Cisco Catalyst LAN switch models are affected by this vulnerability--
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The Catalyst 12xx family, running supervisor software versions up to
and including 4.29.
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The Catalyst 29xx family (but not the Catalyst
2900XL), running supervisor software versions up to and including 2.1(5),
2.1(501), and 2.1(502). This includes the Catalyst 2901, 2902, and 2903
switches. Catalyst 2926 switches are not affected, because
the Catalyst 2926 was not released until after the software fix was made.
Catalyst 2900XL switches run unrelated software, and are
not affected by this vulnerability.
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The Catalyst 5xxx series (including the Catalyst 55xx family),
running supervisor software versions up to and including 2.1(5), 2.1(501), and
2.1(502).
Fixed software for the Catalyst 5xxx and Catalyst 29xx series began shipping with new switches in mid-1997. Sales of the Catalyst 12xx family were stopped before the release of software version 4.30; if you have not upgraded your software since installing your Catalyst 12xx switch, you are affected by this vulnerability.
The affected Cisco Catalyst LAN switches are rack-mountable units typically found in data centers and cable closets.
Products Confirmed Not Vulnerable
Catalyst 5xxx and 29xx switches running versions 2.1(6) and later are not affected. Catalyst 12xx switches running versions 4.30 and later are not affected. Some Cisco Catalyst switches include intelligent modules that run software independent of the supervisor software. These modules, which include a variety of media controllers as well as the route switch module (RSM), are not affected.
No other Cisco products are currently known to be affected by these vulnerabilities.
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The Catalyst 12xx family, running supervisor software versions up to
and including 4.29.
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For the Catalyst 29xx and Catalyst 5xxx switches, this vulnerability has Cisco bug ID CSCdi74333. The bug is present in all supervisor software versions through 2.1(5), including the spot fix releases 2.1(501) and 2.1(502). The bug is fixed in 2.1(6) and later versions, including all 2.2, 2.3, and 2.4 versions, and all 3.x, 4.x, and later versions.
For the Catalyst 1200, this vulnerability has Cisco bug ID CSCdj71684. The bug is present in all software versions through 4.29, and is fixed in 4.30 and later versions.
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This vulnerability may be worked around by assigning no IP addresses to affected Cisco Catalyst switches. However, this workaround will have the effect of disabling all remote management of those switches.
Another possible workaround is to use the filtering capabilities of surrounding routers and/or dedicated firewall devices to prevent untrusted hosts from making connections to TCP port 7161 on affected switches.
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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.
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Cisco knows of no public announcements or discussion of this vulnerability before the date of this notice. Cisco has had no reports of malicious exploitation of this vulnerability. These bugs were identified and reported by outside companies conducting laboratory testing.
No special tools, and only the most basic of skills, are needed to exploit this vulnerability. It would not be difficult for a person with minimal sophistication to find a way to exploit this vulnerability.
Cisco thanks the Internet Security Systems (ISS) X-Force, for independently discovering this matter and bringing it to the attention of Cisco's Product Security Incident Response Team (PSIRT).
The initial report of CSCdi74333 was received before the establishment of the PSIRT, from a customer who has neither requested credit nor given permission to be named in this notice. Cisco security notices do not name or credit third parties without their specific permission.
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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.
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