Posts by asterite
Unknocking was a networking task on CyBRICS CTF 2019 quals.
This is a RCE-as-a-service that runs COBOL code encoded in punch card images upladed by user. Hard parts are generating valid punch card images with desired code and writing COBOL that runs shellcode using available charset. Patch is
chmod -r data(disable listing in service data dir as flags are in randomly-named files).
refrain was a misc task at 0CTF/TCTF Quals 2019 where you had to reconstruct input data from a program trace.