Imperva SecureSphere WAF 11.5 Bypass

Imperva SecureSphere WAF version 11.5 suffers from a bypass vulnerability due to first validating that a Content-Type header must be passed.

MD5 | 64e8407adb3a1ec56bc9a51ab5a506a1

Hello everyone,

Can I have your opinion about this bug below please ?

# Exploit Title: Policy Bypass on Imperva SecureSphere Web Application
# Date: 08/05/2018
# Author: Damien CabriA(c)
# Contact:
# Vendor Homepage:
# Version: Imperva SecureSphere WAF 11.5 in all deployment options
# Tested on: Imperva SecureSphere WAF (bridge and reverse proxy
# Class: Policy Bypass


The Imperva WAF provides solutions to protect websites against attacks (SQL
injections, cross site scripting, illegal resource access). The protect is
base with policies building from Signatures (network, generic attack, known
web application vulnerabilities), Application profiling and Threatradar
Reputation Service.

There is a bug in the Web Correlation Policy engine which protect against
SQLi and XSS.

The WAF is not able to detect malicious SQLi or XSS content in the body of
POST requests without the "Content-Type" header.

An attacker can easily craft a POST request method without the Content-Type
header to bypass firewall protections.

Applications protected by the WAF could be compromised with this bug.

If possible, block POST requests without Content-Type header.

* 08/05/2018 - Initial vendor contact.

* 27/06/2018 - Imperva confirmed the issue. Fix targeted for Q4 2018.

* 12/07/2018 - Ticket closed.

* 18/08/2018 - Public disclosure.


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