Title: Privilege Escalation
Product: Emerson Smart Wireless Gateway
Vendor Homepage: http://emerson.com
Vulnerable Version: 1420 4.6.59
CVE Number: CVE-2020-19417
Authors: Harsha Bhat Anish Mitra and Unmesh Guragol
2019-08-02 Disclosed to the vendor
2019-08-22 Vendor confirmed that the vulnerability was identified
internally and a fix was released in the latest version of firmware
1. Vulnerability Description
Emerson Smart Wireless Gateway 1420 4.6.59 allows non-privileged users
(such as the default account 'maint') to perform administrative tasks by
sending specially crafted HTTP requests to the application.
The PoC explained below is to perform an action accessible ideally only to
an 'administrator' account
Step 1: Using a proxy tool such as Burp Suite, capture an original request
that sets the login banner on the device from a legitimate 'administrator'
Step 2: Logout from the application and login with a low privilege user
account such as 'maint'. This account does not have privileges to set the
Step 3: Replay the original request from 'Step 1' after replacing session
ID of 'administrator' account to that of 'maint' account.
Observe that the application, without validating the permissions set for
'maint' account sets the login banner via the low-privilege account.
The vendor provides an updated version of firmware which should be
CAUTION - This message may contain privileged and confidential information
intended only for the use of the addressee
named above. If you are not the intended recipient of this message you are
hereby notified that any use, dissemination,
distribution or reproduction of this message is prohibited. If you have
received this message in error please notify
The Missing Link immediately. Any views expressed in this message are those
of the individual sender and may not
necessarily reflect the views of The Missing Link.