Check the home directory of flag03 and take note of the files there. There is a crontab that is called every couple of minutes. Files for this level can be found in /home/flag03.
First, let’s check the home directory of our target
Ok we have an empty directory with full access and a shell script who looks like this:
#!/bin/sh for i in /home/flag03/writable.d/* ; do (ulimit -t 5; bash -x "$i") rm -f "$i" done