Pwn:

Echo: [129 solves]

By church

Echo is one of the most famous and simple programs on any system. Nothing can go wrong if I re-implement it, right?

This is a remote challenge, you can connect to the service with: nc echo.challs.srdnlen.it,1091

[echo](<https://ctf.srdnlen.it/api/file/676a23d7-c6fa-45ce-a4b1-9f21f7635fb7/echo?download=&auth=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6MTgsImlhdCI6MTc3MjM0ODkyMiwiZXhwIjoxNzcyMzkyMTIyfQ.V-hKe8hTRjtZ92yBllBXWIo7buB10l_Vddk-i6w-CDc>)

echo.zip

Common offset: [63 solves]

By church

I had an idea: what if we could treat some files as time series? Imagine if when you wrote to a file at a certain offset, that offset was maintained even when you wrote to another file. We'd have a perfect time log of when you wrote what to the files...

I made a dummy implementation of this; take a look.

This is a remote challenge, you can connect to the service with: nc common-offset.challs.srdnlen.it 1089

[common_offset](<https://ctf.srdnlen.it/api/file/59948bd1-8af1-4255-a2cf-f0dec9302b87/common_offset?download=&auth=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6MTgsImlhdCI6MTc3MjM0ODkyMiwiZXhwIjoxNzcyMzkyMTIyfQ.V-hKe8hTRjtZ92yBllBXWIo7buB10l_Vddk-i6w-CDc>)
[libc.so.6](<https://ctf.srdnlen.it/api/file/07c14b18-430c-4000-bfa7-214fbefe5535/libc.so.6?download=&auth=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6MTgsImlhdCI6MTc3MjM0ODkyMiwiZXhwIjoxNzcyMzkyMTIyfQ.V-hKe8hTRjtZ92yBllBXWIo7buB10l_Vddk-i6w-CDc>)
[dockerfile](<https://ctf.srdnlen.it/api/file/a5307791-b557-491e-91b6-13fd88643a7c/dockerfile?auth=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6MTgsImlhdCI6MTc3MjM0ODkyMiwiZXhwIjoxNzcyMzkyMTIyfQ.V-hKe8hTRjtZ92yBllBXWIo7buB10l_Vddk-i6w-CDc>)

common_offset.zip

Registered Stack: [42 solves]

By church

Welcome to the Kingdom of Registered Stack! In this realm, you can only operate with the Stack, and everything must be Registered.

How can i call this? CJail? ASMJail? But above all, is it Turing-complete?

This is a remote challenge, you can connect to the service with: nc registered-stack.challs.srdnlen.it 1090

[registered_stack](<https://ctf.srdnlen.it/api/file/b80a4dc3-6c91-498b-8b77-33755a816bb2/registered_stack?download=&auth=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6MTgsImlhdCI6MTc3MjM0ODkyMiwiZXhwIjoxNzcyMzkyMTIyfQ.V-hKe8hTRjtZ92yBllBXWIo7buB10l_Vddk-i6w-CDc>)
[dockerfile](<https://ctf.srdnlen.it/api/file/39fe779c-075c-4f0f-bf98-039c44834fcd/dockerfile?auth=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6MTgsImlhdCI6MTc3MjM0ODkyMiwiZXhwIjoxNzcyMzkyMTIyfQ.V-hKe8hTRjtZ92yBllBXWIo7buB10l_Vddk-i6w-CDc>)

registered_stack.zip

Linx: [18 solves]

By doliv

You like linking with others, don't you?

This is a remote challenge, you can connect to the service with: nc linx.challs.srdnlen.it 1092

[Dockerfile](<https://ctf.srdnlen.it/api/file/889acacd-1e47-4bbe-a23c-d53537326b00/Dockerfile?auth=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6MTgsImlhdCI6MTc3MjM0NjYyOCwiZXhwIjoxNzcyMzg5ODI4fQ.wu1o1jOWwayf_A6poIt7CCr1UIthMEqf747RiYeg2AY>)
[linx](<https://ctf.srdnlen.it/api/file/3051663a-25d4-43f2-80eb-f275dd3341f3/linx?auth=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6MTgsImlhdCI6MTc3MjM0NjYyOCwiZXhwIjoxNzcyMzg5ODI4fQ.wu1o1jOWwayf_A6poIt7CCr1UIthMEqf747RiYeg2AY>)
[linx.c](<https://ctf.srdnlen.it/api/file/a26c942f-c57a-4518-a30e-a19e81e12c14/linx.c?auth=eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6MTgsImlhdCI6MTc3MjM0NjYyOCwiZXhwIjoxNzcyMzg5ODI4fQ.wu1o1jOWwayf_A6poIt7CCr1UIthMEqf747RiYeg2AY>)

linx.zip

Web:

MSN Revive: [174 solves]