Against B and C versions, just block normally and punish with 5B > 5C+D, etc. Dunno what do do against A version though, I guess just keep blocking (scrubs will usually just keep mashing afterwards so whatever) and prepare to tech a throw on reaction, in case they try to throw you.
You can also use the counter attack thing (pressing forward and A+B immediately after blocking an attack, forgot what it's called <_<) although it will drain half your meter, whether or not it's worth using is up to you.