Moxa AWK-3131A HTTP GET Denial of Service Vulnerability

Summary

An exploitable null pointer dereference exists in the Web Application functionality of Moxa AWK-3131A Wireless Access Point running firmware 1.1. Any HTTP GET request not preceded by an ‘/’ will cause a segmentation fault in the web server. An attacker can send any of a multitude of potentially unexpected HTTP get requests to trigger this vulnerability.

Tested Versions

Moxa AWK-3131A Series Industrial IEEE 802.11a/b/g/n wireless AP/bridge/client 1.1

Product URLs

<http://www.moxa.com/product/AWK-3131A.htm&gt;

CVSSv3 Score

7.5 - CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Details

An exploitable null pointer dereference exists in the Web Application functionality of Moxa AWK-3131A Series Industrial IEEE 802.11a/b/g/n wireless AP/bridge/client. Any HTTP GET request not preceded by an ‘/’ will cause a segmentation fault in the web server. An attacker can send any of a multitude of potentially unexpected HTTP GET requests to trigger this vulnerability.

There is no way to restart the web application using legitimate functionality outside of rebooting the device.

Exploit Proof-of-Concept

The following is one of many HTTP GET requests which will result in a web server segmentation fault: GET a HTTP/1.1

Mitigation

To significantly mitigate risk of exploitation, disable the web application before the device is deployed.

Timeline

2016-11-18 - Vendor Disclosure
2017-04-10 - Public Release