Added third-party c2 section and PaaS C2 subsection

README.md

@@ -34,8 +34,10 @@ THANK YOU to all of the authors of the content referenced in this wiki and to al
 - [Modifying C2 Traffic](#modifying-c2-traffic)
   - [Cobalt Strike](#cobalt-strike)
   - [Empire](#empire)
+- [Third-Party C2 Channels](#third-party-c2-channels)
   - [Domain Fronting](#domain-fronting)
-  - [Further Resources](#further-resources)
+    - [Further Resources on Domain Fronting](#further-resources-on-domain-fronting)
+  - [PaaS Redirectors](#paas-redirectors)
 - [Obscuring Infrastructure](#obscuring-infrastructure)  
 - [Securing Infrastructure](#securing-infrastructure)
 - [General Tips](#general-tips)
@@ -343,7 +345,10 @@ In addition to the Communication Profile, consider customizing the Empire server
 * [Default Empire Communication Profiles (in Empire GitHub repo)](https://github.com/EmpireProject/Empire/tree/master/data/profiles)
 * [How to Make Communication Profiles for Empire - Jeff Dimmock](https://bluescreenofjeff.com/2017-03-01-how-to-make-communication-profiles-for-empire/)
 
-# Domain Fronting
+# Third-Party C2 Channels
+Leveraging trusted, legitimate web services for C2 can provide a valuable leg-up over using domains and infrastructure you've configured yourself. Configuration time and complexity varies based on the technique and service being used. A popular example of leveraging third-party services for C2 redirection is Domain Fronting.
+
+## Domain Fronting
 
 Domain Fronting is a technique used by censorship evasion services and apps to route traffic through legitimate and highly-trusted domains. Popular services that support Domain Fronting include [Google App Engine](https://cloud.google.com/appengine/), [Amazon CloudFront](https://aws.amazon.com/cloudfront/), and [Microsoft Azure](https://azure.microsoft.com/). In a nutshell, traffic uses the DNS and SNI name of the trusted service provider, Google is used in the example below. When the traffic is received by the Edge Server (ex: located at gmail.com), the packet is forwarded to the Origin Server (ex: phish.appspot.com) specified in the packet’s Host header. Depending on the service provider, the Origin Server will either directly forward traffic to a specified domain, which we’ll point to our team server, or a proxy app will be required to perform the final hop forwarding.
 
@@ -354,13 +359,20 @@ For more detailed information about how Domain Fronting works, see the whitepape
 Useful tool to hunt for potential Frontable Domains
 * [FindFrontableDomains](https://github.com/rvrsh3ll/FindFrontableDomains)
 
-## Further Resources
+### Further Resources on Domain Fronting
 * [High-reputation Redirectors and Domain Fronting - Raphael Mudge](https://blog.cobaltstrike.com/2017/02/06/high-reputation-redirectors-and-domain-fronting/)
 * [Empire Domain Fronting Chris Ross (@xorrior)](https://www.xorrior.com/Empire-Domain-Fronting/)
 * [Domain Fronting via Cloudfront Alternate Domains - Vincenty Yiu (@vysecurity)](https://www.mdsec.co.uk/2017/02/domain-fronting-via-cloudfront-alternate-domains/)
 * [Escape and Evasion Egressing Restricted Networks - Tom Steele (@_tomsteele) and Chris Patten](https://www.optiv.com/blog/escape-and-evasion-egressing-restricted-networks)
 * [Red Team Insights on HTTPS Domain Fronting Google Hosts Using Cobalt Strike](https://www.cyberark.com/threat-research-blog/red-team-insights-https-domain-fronting-google-hosts-using-cobalt-strike/) - [Will Vandevanter and Shay Nahari of CyberArk](https://www.cyberark.com)
 
+## PaaS Redirectors
+Many PaaS and SaaS providers provide a static subdomain or URL for use with a provisioned instance. If the associated domain is generally highly trusted, the instances could provide extra trust to your C2 infrastructure over a purchased domain and VPS.
+
+To set the redirection up, you will need to identify a service that issues a static subdomain or URL as part of an instance. Then, either the instance will need to be configured with network or application-based redirection. The instance will act as a proxy, similar to the other redirectors discussed on this wiki.
+
+Specific implementation can vary greatly based on the service; however, for an example using Heroku, check out the blog post [Expand Your Horizon Red Team – Modern SaaS C2](https://cybersyndicates.com/2017/04/expand-your-horizon-red-team/) by [Alex Rymdeko-Harvey (@Killswitch_GUI)](https://twitter.com/Killswitch_GUI).
+
 # Obscuring Infrastructure
 
 Attack infrastructure is often easy to identify, appearing like a shell of a legitimate server. We will need to take additional steps with our infrastructure to increase the likelihood of blending in with real servers amongst either the target organization or services the target may conceivably use.