eula

Challenge author
JP Smith (SIGPwny)
Write-up author
Vanilla (Batman's Kitchen)
Points
400
Category
crypto

throwback to when the aztecs sacked mitlan

eula.py

The script requires us to sign some data with an RSA key we do not know. The RSA key is 2048 bits with e = 3. The script uses Python-RSA and references the date 2015-07-29 and "up to date libraries".

We looked at the history of the Python-RSA project and found this commit, which mentions "Fix BB'06 attack" and affects signing. Interesting… We look up this attack and find this post, complete with attack script. Slot in the message we want to sign, and bingo, signature, and hence flag.