Nullcon CTF 2024

AHHH The field is full of mines! Screw it! I am going in! Authors: @moaath, @Liikt Category: Reversing Solver: lukasrad02 Flag: ENO{H0p3fully_Y0ur_M1ND_D1D_G3t_scr3w3D} Scenario The challenge only consists of a single PowerShell script: ( 'wcyd'|%{${#/~} =+ $()}{ ${@}=${#/~}} { ${/.} = ++${#/~}}{ ${*~}=(${#/~} =${#/~} +${/.})} {${$./} =(${#/~}= ${#/~} + ${/.} )}{${)@}=( ${#/~}=${#/~}+${/.} )} { ${'} =(${#/~} =${#/~}+ ${/.}) } { ${;} = ( ${#/~}=${#/~} + ${/.}) } {${ *-}= ( ${#/~}=${#/~}+${/....

Lost in Parity I deleted the flag. python3 xor.py ./f* > xor rm xor.py flag.txt Author: @miko Category: misc Solver: frcroth, mp455 Flag: ENO{R41D1NG_F1L3S_4R3_W3?} The challenge gives us a bunch of files - 255 files and the xor-file. A quick random sample of wc -c suggests that all files including the xor-file have the same size: 26 bytes. The challenge description hints that the xor-file might be the result of applying the xor-operation to the 255 files and the flag....

Itchy Route Get straight to the point and list your options! Category: misc Solver: frcroth, mp455 Flag: ENO{4NY_M0R3_QU35T10N5M4RK5_0C?N?} When connecting to this challenge, nothing greets us and if we are polite and ask “hello”, it responds with: Request contained some illegal characters: “hello” Also, when we take too long, we get different errors, e.g.: Request timeout: firewall getting suspicious. This already tells us that we probably need to use a script to interact here, since we won’t be able to type quickly enough....

missingcat Where is my cat? 😿 Category: misc Solver: frcroth, mp455 Flag: ENO{0xCAT_BUT_H4PP1_THANK_Y0U!} We were given the following script: import subprocess cmd = input("Give me your command: ") if len(cmd) > 2: print("Command is too long!") try: cmdstring = [cmd, "flag.txt"] print(f"Executed command: {cmdstring}") result = subprocess.check_output(cmdstring, timeout=1) except: result = b"No 😿" print(result.decode()) So we need to find a command that gives us the flag and whose name is only 2 letters long....

Timecode Times change you, and numbers. Category: misc Solver: frcroth, mp455 Flag: ENO{S0M3_J4V4_1NT3G3R5_4R3_C4CH3D} When we connect to the host, we get a challenge: Registered as user b6ee888b-6f24-4049-b0e2-ee227233973f New Challenge (2024-03-20T19:57:49.535Z) 69 51 97 43 01 65 After trying out some values, sending the same numbers gives a cryptic response: 69 51 97 43 01 65 ‘85’ is not equal to ‘69’ ‘66’ is not equal to ‘51’ ‘79’ is not equal to ‘97’ ‘86’ is not equal to ‘43’ ‘127’ is not equal to ‘01’ ‘95’ is not equal to ‘65’ Challenge failed....