It turns out that Maven Central only lets you use SSL if you purchase an authentication token for a donation of $10. They claim this $10 will go to the Apache project, but that's besides the point.

SSL encryption requires a separate authentication token. To see what I mean, try opening http://central.maven.org/maven2/org/springframework/ and https://central.maven.org/maven2/org/springframework/ in your browser. This means that package managers like Clojure's lein, Scala's sbt, and maven itself when not specially configured will download JARs without any SSL.

Dilettante is a man in the middle proxy that injects malicious codes into JARs served by Maven Central.

1. Get in a position where you can man-in-the-middle HTTP traffic. Some hints:

   • Buy a wifi router, call it "Starbucks Wifi"
   • Install ettercap
   • Happen to be an ISP
   • Something something

2. Run dilettante.py

3. Proxy your target's http traffic through localhost:8080

   • You can do an easy PoC of this by setting the <proxy> setting in ~/.m2/settings.xml

Your victims will get a friendly image when they execute any Java code that uses a JAR that passed through dilettante.

You can see a video here