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Handling Missed Vulnerabilities

Wednesday, April 5, 2017

(Originally posted at https://nvisium.com/blog/2017/04/05/handling-missed-vulnerabilities/.)

Robin "digininja" Wood wrote this interesting article about the impact of missing vulnerabilities during security assessments. He makes a lot of good points, and the reality is, it's something we all deal with. Robin talks about how missing a vulnerability can be the end of one's career, or at least a large step backward. While this is true, his article only addresses the impact at a micro level. I'd like to expand on that. ... more


Proxying thru Virtual Client VPNs

Thursday, December 1, 2016

So, I'm sorta OCD. Anyone that knows me will attest to that. When it comes to my computing environments, I can't stand clutter. That includes both the external and internal components of my computing environment. One particular point of interest for me is the number of applications installed on my system. I've always felt like limiting the amount of software on my system to only what I needed, and avoiding endless install and uninstall cycles, has resulted in a more stable system. I have no scientific proof to back this up, but it's always worked for me, so I like to keep my system clean and tidy. However, in my line of work, where one-off tools for testing and research abound, this is a daily challenge. ... more


Fun with XSShell

Friday, July 15, 2016

So this is kinda fun. With this page open, copy and paste one of the listener commands from below into a terminal window on your local machine. Then, paste alert(42) into the resulting shell and press "Enter". Once you recover from the initial shock of what you just witnessed, play with the following payloads and spend the next hour of life thoroughly enjoying yourself. ... more


Exploring SSTI in Flask/Jinja2 - Part 2

Friday, March 11, 2016

I recently wrote this article about exploring the true impact of Server-Side Template Injection (SSTI) in applications leveraging the Flask/Jinja2 development stack. My initial goal was to find a path to file or operating system access. I was previously unable to do so, but thanks to some feedback on the initial article, I have since been able to achieve that goal. This article is the result of the additional research. ... more


Exploring SSTI in Flask/Jinja2

Wednesday, March 9, 2016

This is the first of two articles covering research into SSTI in the Flask/Jinja2 development stack. This article only tells half the story, but an important half that provides context to the final hack. Please consider reading both parts in their entirety. Part 2 can be found here. ... more


Validating Redirects with Hyperlinks

Wednesday, December 2, 2015

I came across an application recently that contained an Unvalidated Redirect flaw. The flaw was pretty basic. The login page accepted a next parameter and blindly redirected to the value of the parameter without validating whether or not the value represented a trusted destination. The redirect occurred in client-side logic without the parameter ever hitting the server. My recommendation to the client included a pretty basic JavaScript validation filter, and they quickly implemented a fix and sent the code back for me to validate if the flaw had been remediated. In looking at the code, I realized that they had not implemented my recommended code, but did something that I had not seen before and thought was quite novel. Hence, why I am writing this. ... more


Regex: Regularly Exploitable

Thursday, June 11, 2015

Here's a quick demonstration of why Regular Expressions (regex) can be bad for implementing character whitelisting. ... more