VeriSign, Inc.® US Home | Worldwide Sites | Site Map
Products & Services Solutions Support About VeriSign Login for existing VeriSign customers
You Are Here: US Home > VeriSign iDefense Security Intelligence Service > Current Intelligence > Vulnerability Advisories > 2002 > 11.19.02

Denial of Service Vulnerability in Linksys Cable/DSL Routers

I. BACKGROUND

Linksys Group Inc. currently sells several broadband router products, including:

BEFW11S4, Wireless Access Point Router with 4-Port Switch - Version 2
BEFSR11, EtherFast® Cable/DSL Router
BEFSR41, EtherFast® Cable/DSL Router with 4-Port Switch
BEFSRU31, EtherFast® Cable/DSL Router with USB and 3-Port Switch

More information is available at http://www.linksys.com/products/group.asp?grid=23 .

II. DESCRIPTION

The BEFW11S4, BEFSR11, BEFSR41 and BEFSRU31 can be crashed when several thousand characters are passed in the password field of the device's web management interface. Exploitation simply requires the use of a web browser that can send long Basic Authentication fields to the affected router's interface.

III. ANALYSIS

Remote exploitation is only possible if the remote web management interface is enabled (this is disabled by default). An attacker on the internal network can access the web management interface by using a web browser and accessing the URL http://192.168.1.1 (default URL).

IV. DETECTION

The BEFW11S4, BEFSR11, BEFSR41, and BEFSRU31 devices with firmware
earlier than version 1.43.3 are affected.  iDEFENSE confirmed susceptibility on the BEFW11S4. Linksys indicated that the BEFSR11, BEFSR41 and BEFSRU31 are also affected.

V. WORKAROUND

Disable the remote web management interface on the affected router.

VI. RECOVERY

Cycling power through the affected device should restore normal functionality; pressing the "Reset" button on the router is insufficient.

VII. VENDOR FIX

Linksys firmware 1.43.3, which is available at http://www.linksys.com/download/, fixes the problem on all the affected devices.

VIII. CVE INFORMATION

The Mitre Corp.'s Common Vulnerabilities and Exposures (CVE) Project assigned the identification number CAN-2002-1312 to this issue.

IX. DISCLOSURE TIMELINE

11/02/2002 Issue disclosed to iDEFENSE
11/06/2002 Linksys notified (jay.price@linksys.com)
11/11/2002 Linksys response (diana.ying@linksys.com)
11/18/2002 iDEFENSE clients notified
11/19/2002 Public disclosure


X. CREDIT

Alex S. Harasic (aharasic@terra.cl) discovered this vulnerability.


Need more information?
Speak with a service representative at 650-426-5310 Request information online


Contact Us
Please contact sales at
650-426-5310 or
submit your inquiry online.
VeriSign iDefense Security Intelligence Service
Security Intelligence Service Levels
Alerts, Reports, and Briefings
Methodology
Research and Response Teams
Current Intelligence
Topical Research Reports
Vulnerability Advisories
Malicious Code Advisories
Information Center
Security Intelligence Webcasts
Proactive Security Intelligence
Intelligence for Patch Management
Early Threat Warning
Contact Us Careers Legal Notices Privacy Repository ©1995-2007 VeriSign, Inc. All rights reserved.
Products & Services  :  Solutions  :  Support  :  About VeriSign  :  Existing Customers
US Home  :  Worldwide Sites  :  Site Map  :  Search
VeriSign (Nasdaq: VRSN) operates intelligent infrastructure services that enable and protect billions of interactions across the world's voice and data networks. VeriSign offerings include SSL Certificates, two-factor authentication, identity protection, managed network security, public key infrastructure (PKI), security consulting, information management, as well as solutions for intelligent communications, commerce, and content. VeriSign is also building next-generation service offerings for emerging opportunities such as RFID-enabled supply chains, VoIP technology, and digital-content distribution over mobile and broadband networks.