Traditionally, Bugzilla hasn't had very strong antispam measures. This has become a major issue for some public installations. For example, the Eclipse project now requires explicit permission for new users to open bugs:
https://bugzilla.mozilla.org/show_bug.cgi?id=1306750
We've been getting spam on bugs.wireshark.org but fortunately for us the volume is still low and it's easy enough to just set the "private" flag on the offending bugs. However, we have a separate self-inflicted issue. We log bug activity via the wireshark-bugs mailing list and those messages are archived, which effectively means we provide cheap and easy spam hosting at a popular web address. Cleaning up these messages is an inconvenient and manual process.
As a result I'm disabling the archive feature on the wireshark-bugs mailing list this upcoming Saturday, December 31. The mailing list itself will still be up and running and old archived messages will still be available, but new messages will not be archived after that date.