MD5 - Dictionary attack

[undeath]

Use hash mode 20 and specify the timestamp as salt. Then create a rule file to append the user and specify it last on the hashcat command line

then you can run hashcat like this:

hashcat -m 20 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa:20200414073337 -r rules.rule -r more_rules.rule -r append_user.rule wordlist.txt