About

I am:

  • A senior cloud researcher and advocate @ Datadog
  • The former cloud penetration testing lead @ Bishop Fox
  • The founder and co-organizer of IthacaSec
  • A way-past-my-prime soccer player
  • A hobbyist woodworker and gardener

I have:

  • Had some nice conversations: 

Say hi:

Comments

Post a Comment

Popular posts from this blog

Exploiting Python Code Injection in Web Applications

Image
A web application vulnerable to Python code injection allows you to send Python code though the application to the Python interpreter on the target server. If you can execute python, you can likely call operating system commands. If you can run operating system commands, you can read/write files that you have access to, and potentially even launch a remote interactive shell (e.g., nc, Metasploit, Empire). The thing is, when I needed to exploit this on an external penetration test recently, I had a hard time finding information online about how to move from proof of concept (POC) to useful web application exploitation. Together with my colleague Charlie Worrell ( @decidedlygray ),  we were able to turn the Burp POC (sleep for 20 seconds) into a non interactive shell, which is what this post covers. Python code injection is a subset of server-side code injection, as this vulnerability can occur in many other languages (e.g., Perl and Ruby). In fact, for those of you who are CWE fans
Read more

Exploiting Server Side Request Forgery on a Node/Express Application (hosted on Amazon EC2)

Image
I recently came across a Server Side Request Forgery (SSRF) vulnerability within an application that I assessed.  The application was hosted on Amazon EC2 and was using Node.js, Express.js, and as I found out later, Needle.js. Discovery   Manual Discovery In the discovery phase, I noticed a function of the application that was taking a user specified URL and displaying the first paragraph from that URL into the page.  This application allowed a user to share a URL with their friends, and grabbing the first paragraph was a feature that would provide the friends with more context. The thing is, when looking at my Burp history, I could not find the request to the URL that I specified in my logs.  This should raise an eyebrow!   This means that the server is taking the URL I specified, making a request on my behalf, and then returning the result to me. That right there is SSRF .  Then, the only question was: What is the risk? Automated Discovery Since April 2015, if you a
Read more

Pentest Home Lab - 0x3 - Kerberoasting: Creating SPNs so you can roast them

Image
TL;DR There are a lot of great blogs out there that show you how to Kerberoast.  In this post, I'm going to walk through the process of setting up your lab so that you can practice this attack.  This involves creating a domain user and then mapping a SPN to that account. After that, I'll walk through using Empire to launch Invoke-Kerberoast, and I'll crack the hashes offline with Hashcat. Pentest Home Lab Recap If you don't already have an Active Directory lab and want to build one so that you can play along, check out my previous posts: Pentest Home Lab - 0x0 - Building A Virtual Corporate Domain   Pentest Home Lab - 0x1 - Building Your AD Lab on AWS Pentest Home Lab - 0x2 - Building Your AD Lab on Premises using Proxmox VE The Attack: Kerberoasting Attack Goals Domain privesc & lateral movement.  If you have domain credentials and access to the domain, this is a relatively easy way to gain additional access within the domain. If all goes well, you
Read more