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CERT Coordination Center

Cisco IOS/X12-X15 has default SNMP read/write string of "cable-docsis"

Vulnerability Note VU#840665

Original Release Date: 2001-05-01 | Last Revised: 2002-03-05


There is a vulnerability that permits unauthorized access to several switch and router products manufactured by Cisco Systems. An attacker who gains access to an affected device can read and modify its configuration, creating a denial-of-service condition, an information leak, or both.


Certain versions of the Cisco Internetworking Operating System (IOS) contain a default Simple Network Management Protocol (SNMP) community string that unintentionally grants read-write access to many SNMP objects. The default community string ("cable-docsis") is present in a Management Information Base (MIB) module used to configure cable modem equipment that is compatible with the Data Over Cable Service Interface Specification (DOCSIS) standard. When present on non-DOCSIS equipment, this community string grants an attacker complete access to affected devices, allowing them to gather information, monitor network traffic, and alter or disrupt network operation.


This vulnerability allows attackers to read and modify any SNMP object present on an affected device. Attackers exploiting this vulnerability can re-route or disrupt network traffic as well as gather information about network topology and system administration contacts.


Cisco has released an advisory that provides a list of affected products, along with instructions for obtaining fixed software. Because there are many possible combinations of hardware and software configurations, the CERT/CC recommends that all users of IOS software consult the following Cisco Security Advisory:

Cisco has provided detailed information on implementing workarounds to address this issue. Please consult the Cisco advisory referenced above.

Vendor Information


Cisco Affected

Updated:  March 16, 2001



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.


The CERT/CC has no additional comments at this time.

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

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The CERT/CC thanks Ben Boulanger of Speedtrak Communications for reporting this vulnerability to us and Cisco Systems for their description and patch.

This document was written by Jeffrey P. Lanza and is based on information obtained from a Cisco Security Advisory.

Other Information

CVE IDs: None
Severity Metric: 54.68
Date Public: 2001-02-28
Date First Published: 2001-05-01
Date Last Updated: 2002-03-05 20:35 UTC
Document Revision: 16

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