Hashcat can't crack salted MD5?

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you're wrong. i guess you want to crack ipb2 or mybb which are the most popular software to use md5( md5($salt) . md5($pass) );

you can simply use -m 2811 to crack it.

you can not use -m 3710 because "ceb20772e0c9d240c75eb26b0e37abee2fe04e524ba40505a82e03a2819429cc" is > length 55 and therefore would need to call another transform round which makes the cracking slow. therefore use -m 2811 which is optimized to do this and precomputes md5(salt) in the startup phase once