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Showing posts from June, 2021

Introducing Striker and the Payload Automation Libraries

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TL;DR – Striker, Compyler, Artifactor, Sleepy, and Detemplate are a set of Python libraries we created to help make building custom payloads faster, more consistent, and more OPSEC safe and allow for better IoC tracking during Red Team operations. The libraries can be found on GitHub here: https://github.com/emcghee/PayloadAutomation . Introduction During an operation, we were creating a custom initial access payload which would execute a Cobalt Strike Beacon. The payload was fairly complex with multiple components coming together and multiple steps to obfuscate the shellcode before embedding it into the payload. During the preparation phase of the operation, we went through multiple profile and listener variations and needed to test our initial access payload with each variation. This meant that I had to go into the GUI for Cobalt Strike, generate the shellcode and save it to a file, manually encrypt and obfuscate it, embed it in my payload, then compile. This process tended to be ...
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No Shells Required - a Walkthrough on Using Impacket and Kerberos to Delegate Your Way to DA

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There are a ton of great resources that have been released in the past few years on a multitude of Kerberos delegation abuse avenues.   However, most of the guidance out there is pretty in-depth and/or focuses on the usage of @Harmj0y’s Rubeus.   While Rubeus is a super well-written tool that can do quite a few things extremely well, in engagements where I’m already running off of a primarily Linux environment, having tools that function on that platform can be beneficial.   To that end, all the functionality we need to perform unconstrained, constrained, and resource-based constrained delegation attacks is already available to us in the impacket suite of tools. This post will cover how to identify potential delegation attack paths, when you would want to use them, and give detailed  walkthroughs  of how to perform them on a Linux platform.   What we won’t be covering in this guide is a detailed background of Kerberos authentication, or how various type...
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Executing Macros From a DOCX With Remote Template Injection

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The What: In this post, I want to talk about and show off a code execution method which was shown to me a little while back. This method allows one to create a DOCX document which will load up and allow a user to execute macros using a remote DOTM template file. This attack has been seen in the wild, is partially included in open-source offensive security tools , as has been blogged about by Cisco Talos , but in the blog post and the open-source tool, it is only seen as a credential stealing attack typically over the SMB protocol. This blog post will detail how to use this method to download a macro-enabled template over HTTP(S) in a proxy-aware method into a DOCX document. The Why: The benefit of this attack versus a traditional macro enabled document is multidimensional. When executing a phishing attack against a target, you able to attach the .docx directly to the email and you are very unlikely to get blocked based on the file extension. Many organizations block .doc or .do...
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One Click to Compromise -- Fun With ClickOnce Deployment Manifests

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Note: I submitted a report to MSRC regarding the hash-disclosure vulnerability associated with ClickOnce deployment manifests. After review I got a response back earlier in July where it was noted that the vulnerability did not meet the bar for immediate servicing and was given the green light to disclose. Edit 9/22:  MS has remediated the NTLM-disclosure part of this issue as of KB4576630 https://support.microsoft.com/en-us/help/4576630/kb4576630   However, this method will still work as a delivery mechanism for stage-0 payloads. TL;DR ClickOnce Deployment Manifests are a relatively unknown way to both get an initial payload into an environment as well as remotely retrieve NTLM challenge-response hashes over HTTP.  Hash retrieval occurs on initial file open (before any warnings pop) meaning that even if the user opts to close out on the warning, we still have a hash we can attempt to crack.   IE also has some interesting interactions with these files and will au...
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