Tokyo Westerns CTF 2017 – Palindromes Pairs (Challenge Phase)

This challenge was a follow-up to an earlier challenge, titled "Palindromes Pairs - Coding Phase". In that earlier warmup ppc challenge, the goal was to write an algorithm to solve the following problem: given up to 1000 strings $latex s_i$, each of length at most 1000, count the number of pairs $latex (i, j)$ such… Continue reading Tokyo Westerns CTF 2017 – Palindromes Pairs (Challenge Phase)

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33C3 CTF – shjail

The goal of this challenge is to successfully run (in a shell on a provided server) a setuid binary flag which asks you to repeat a number, and then (if you repeat it successfully) outputs the flag: This would be trivial but for one interesting restriction of the provided shell: the only characters you are… Continue reading 33C3 CTF – shjail

SharifCTF 7 – Bsniff

Bsniff was a packet capture file consisting of DNS requests to blockchain.info and GET requests of the form blockchain.info/q/addressbalance/[bitcoin address]?confirmations=6. Here is a Wireshark screenshot with those things: Looking at the HTTP packet details, we can see that the User-Agent is python-requests, suggesting that this pcap basically consists of a Python script making requests to… Continue reading SharifCTF 7 – Bsniff