Tags: crypto rsa 

Rating: 5.0

RSA blinding attack
* possibility to execute commands on the server
* commands must be signed before being executed
* required command 'cat flag' cannot be signed because of blacklisted 'cat' command
* adjust command 'cat flag' with blinding factor
* sign adjusted command
* calculate signature for original command 'cat flag'
* execute command with valid signature

Original writeup (https://devel0pment.de/?p=1210).