hashcat
advanced password recovery

how to crack this kind of hashes with hashcat?
md5(md5($pass).$salt)

i think this hash mode was in very old versions of hashcat. but why it is removed?

This is the algo used by vbulletin, see the --help output:
hashcat supports:
-m 2611 = vBulletin < v3.8.5
and
-m 2711 = vBulletin >= v3.8.5

the difference is mainly the supported salt length (salts for 2711 are longer)