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Own a Cisco modem or wireless gateway? It might be owned by someone else, too

Remote code exec in HTTP server hands kit to bad guys

A number of Cisco home network gateways have a security bug that allows attackers to hijack the devices remotely. A firmware update to close the hole is being rolled out to ISPs to deploy.

The networking giant said that certain Wireless Home Gateway products are vulnerable to a remote-code execution attack, which is triggered by sending a specially crafted HTTP request to the web server running on the hardware.

Cisco said "the vulnerability is due to incorrect input validation for HTTP requests," which allows "an unauthenticated, remote attacker to exploit a buffer overflow and cause arbitrary code execution."

"Successful exploitation could allow the attacker to crash the web server and execute arbitrary code with elevated privileges," we're told. "There are currently no known workarounds available for this vulnerability."

The vulnerable products are:

  • Cisco DPC3212 VoIP Cable Modem
  • Cisco DPC3825 8x4 DOCSIS 3.0 Wireless Residential Gateway
  • Cisco EPC3212 VoIP Cable Modem
  • Cisco EPC3825 8x4 DOCSIS 3.0 Wireless Residential Gateway
  • Cisco Model DPC3010 DOCSIS 3.0 8x4 Cable Modem
  • Cisco Model DPC3925 8x4 DOCSIS 3.0 with Wireless Residential Gateway with EDVA
  • Cisco Model DPQ3925 8x4 DOCSIS 3.0 Wireless Residential Gateway with EDVA
  • Cisco Model EPC3010 DOCSIS 3.0 Cable Modem
  • Cisco Model EPC3925 8x4 DOCSIS 3.0 with Wireless Residential Gateway with EDVA

According to Cisco, the flaw is present on the devices whether they are operating as internet access gateways or as wireless routers on home or small office gateways. The bug was reported to Cisco by Chris Watts of Tech Analysis.

The networking biz has distributed a patch to broadband providers to pass onto affected home and small office customers.

The HTTP web server is provided in the devices' firmware to allow them to be configured from across the public internet. For example, the documentation for the vulnerable DPC3825 and EPC3825 models reads: "The protocol HTTP is required for remote management. To remotely access the device, enter https://xxx.xxx.xxx.xxx:8080 (the x's represent the device's public Internet IP address, and 8080 represents the specified port) in your web browser's address field."

Although this remote management feature can be disabled in the aforementioned devices, Cisco says there is no workaround for the bug.

The disclosure comes just one day after Oracle threatened to drown admins in a deluge of 113 patches, including 20 for Java. Last week, Microsoft and Adobe posted their July scheduled security updates, fixing three critical bugs in total. ®

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