Truncated IPMI Passwords

by Anton Semjonov

tl;dr: webui truncates new passwords to 19 chars

I used KeePassX to generate a new, 24 character password with all character types enabled. This was supposed to replace the default ADMIN/ADMIN combination for IPMI on my ESXi box. So I opened the appropriate page through a browser, navigated to Configuration > Users and modified the ADMIN user.

It happily accepted the new password with no warning whatsoever and I logged out to test it .. oh well .. it didn’t work.

While poking around for a way to reset the password, I found this article: Supermicro IPMI – password vulnerability. The mentioned port is closed in my firmware, so I’ve got that going for me. Reading on, I found out that IPMI truncates long passwords entered through the web administration page.

Gah! My Samsung printer does that too .. whoever thought this was a great idea?! Anyway. Use the first 19 characters of whatever password you’ve set through the web interface and you’ll be allowed back in.