There are popular trojans made with Delphi?
Loads of'm.
Often using KOL. More than once just the use of KOL's reduced system units was enough to trigger false positives.
Some of their writers "education" came from here:
http://www.delphibasics.info/home/delphibasicssnippets/archiveStill interesting for low-level Pascal lovers.
- hiding applications from processmanager
- dll injection
- communications: 4k multithreaded webserver etc etc
- all types of hooking available to mankind.
- using slack or raw disk space
- Attach to a running process
Most of what you need is still there...
Real fun.
Of course the world has moved on and user space trojans are not really recommended to write unless you want to go to rest your feet for a couple of years.
Note all those snippets on their own are perfectly legal, just knotting them together in any meaningful way isn't