Quick-reference links for getting started with machine learning

BackdoorCTF 2017 Fun Signals: using Linux signal handlers as a ret2syscall exploit primitive

BackdoorCTF 2017 ECB: exploiting AES-ECB pattern leakage to reveal an encrypted image flag

Cracking a Vigenère cipher and XOR-encoded PNG to reveal the hidden flag

Reversing a binary with XOR-encoded flag hidden in a lookup table

Walkthroughs for fd, collision, bof, flag, and passcode challenges on pwnable.kr

BackdoorCTF 2016 enter the matrix: binary exploitation to reach the flag on a remote server

BackdoorCTF 2016 debug: reversing a 32-bit binary and hashing the result with SHA256

BackdoorCTF 2016 buzybee: forensics challenge extracting a flag virus from infected files

BackdoorCTF 2016 imagelover: web exploitation via malicious image upload

BackdoorCTF 2016 isolve: auto-generating regex-matching strings with exrex under a time limit

BackdoorCTF 2016 jigsaw: manually reassembling 64 image pieces to decode 16 characters

BackdoorCTF 2016 intro16: collecting flag fragments from IRC and Twitter

Using a setuid binary to read a file owned by another user

Bypassing .bashrc logout by running a command directly over SSH

Using diff to find the one changed line between two password files

Port scanning with nmap to find the SSL listener and get an SSH key

Submitting a password over SSL using openssl s_client

Submitting a password to a localhost port using netcat

Using an SSH private key to log in without a password

Decompressing a repeatedly-compressed hexdump with xxd, gzip, bzip2, and tar

Decoding a ROT13 cipher using the tr command

Decoding base64-encoded data with the base64 command

Using strings to extract human-readable text from a binary file

Finding the only unique line in a file using sort and uniq -u

Extracting a password next to the word 'millionth' with grep

Searching the whole server by owner, group, and size with find

Using find with a size filter to locate the password among many decoy files

Using the file command to find the only human-readable file

Finding and reading a hidden file with ls -a

Reading a filename with spaces using quotes or backslash

Reading a file named with a dash using a path prefix

Logging into SSH and reading a file with cat

Decoding a QR code and then Morse code to reveal the flag.

Using the file command to unmask a fake broken image and recover the flag.

Spotting the hidden flag by viewing the page's HTML source.