Vulnerability Note VU#840665

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

Original Release date: 01 May 2001 | Last revised: 05 Mar 2002


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.

Systems Affected (Learn More)

VendorStatusDate NotifiedDate Updated
CiscoAffected-16 Mar 2001
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



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: Unknown
  • Date Public: 28 Feb 2001
  • Date First Published: 01 May 2001
  • Date Last Updated: 05 Mar 2002
  • Severity Metric: 54.67
  • Document Revision: 16


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