pake1.rb pake2.rb Summary: attacking password-based key exchange schemes based on SPEKE with MITM.
Tag: ctf
Oct 03
TUM CTF 2016 – Shaman (Crypto 500)
Oh great shaman! Somehow the village idiot got his hands on this fancy control machine controlling things. Obviously, we also want to control things (who wouldn’t?), so we reverse-engineered the code. Unfortunately, the machine is cryptographically protected against misuse. Could you please maybe spend a few seconds of your inestimably valuable time to break that …
Oct 02
TUM CTF 2016 – Tacos (Crypto 400)
All my fine arts and philosophy student friends claim discrete logarithms are hard. Prove them wrong. nc 104.198.63.175 1729 vuln_tacos.py Summary: bypassing Fermat primality test with Carmichael numbers and solving discrete logarithm using Pohlig-Hellman algorithm.
Oct 02
TUM CTF 2016 – ndis (Crypto 300)
We have a HTTPS server and client talking to each other with you right in the middle! The client essentially executes curl –cacert server.crt https://nsa.gov with some magic to redirect the transmitted data to your socket, to which the server responds with a lovely German-language poem. NOTE: There is nothing else hosted on the server; …
Sep 19
CSAW Quals 2016 – Broken Box (Crypto 300 + 400)
I made a RSA signature box, but the hardware is too old that sometimes it returns me different answers… can you fix it for me?} e = 0x10001 nc crypto.chal.csaw.io 8002 Summary: fault attack on RSA signatures, factoring using private exponent exposure.
Sep 05
Tokyo Westerns/MMA CTF 2016 – Backdoored Crypto System (Reverse+Crypto 400)
Get the flag. bcs.7z $ nc bcs.chal.ctf.westerns.tokyo 3971 Summary: recovering AES key from partial subkey leaks.
Sep 05
Tokyo Westerns/MMA CTF 2016 – Pinhole Attack (Crypto 500)
Decrypt the cipher text with a pinhole. $ nc cry1.chal.ctf.westerns.tokyo 23464 pinhole.7z Summary: attacking RSA using decryption oracle leaking 2 consecutive bits in the middle.
May 03
Google CTF – Woodman (Crypto 100)
How honest are you? Running here Summary: breaking a weak PRNG
May 01
Google CTF – Spotted Wobbegong (Crypto 100)
Are you able to defeat 1024-bit RSA? public.pem Summary: breaking RSA with PCKS v1.5 padding and exponent 3.
May 01
Google CTF – Jekyll (Crypto)
Can you access the admin page? You can look at the crypto here. source.py Summary: finding a preimage for a simple 64-bit ARX-based hash.
May 01
Google CTF – Wolf Spider (Crypto 125)
Continuing on from Eucalypt Forest – can you break Message Authentication in Wolf Spider wolf.py Summary: forging signatures by exploiting CBC padding oracle and hash length extenstion
Apr 24
PlaidCTF 2016 – sexec (Crypto 300)
If you need to securely grant execution privileges, what better way to do it than sexec? This is running on sexec.pwning.xxx:9999 sexec.tar.gz Summary: attacking a small instance of Ring-LWE based cryptosystem with Babai’s Nearest Vector algorithm.
Mar 07
Boston Key Party CTF 2016 – Feistel (Crypto 5pts)
feistel – 5 – 15 solves : crypto: I just made a brand new cipher! Can you recover the key? 52.86.232.163:32785 feistel.go Summary: slide with a twist attack
Mar 07
Boston Key Party CTF 2016 – GCM (Crypto 9pts)
[8] : gsilvis counting magic – 9 – 4 solves : crypto: Here’s a verification/decryption server: gcm.ctf.bostonkey.party:32768 . Get the GCM MAC key (the thing the server prints out on startup). We’ve given you one valid ciphertext to get you started. It has iv: [102 97 110 116 97 115 116 105 99 32 105 …
Mar 07
Boston Key Party CTF 2016 – HMAC-CRC (Crypto 5pts)
[3] : hmac_crc – 5 – 36 solves : crypto: We’re trying a new mac here at BKP—HMAC-CRC. The hmac (with our key) of “zupe zecret” is ‘0xa57d43a032feb286’. What’s the hmac of “BKPCTF”? hmac-task.py Summary: breaking HMAC-CRC (again)