Title: Privilege Escalation  
Product: Emerson Smart Wireless Gateway  
Vendor Homepage:  
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.  
2. PoC  
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  
login banner.  
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.  
3. Solution  
The vendor provides an updated version of firmware which should be  
installed immediately.  
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