https://phabricator.wikimedia.org/p/Qse24h/ just mass-closed many tasks as duplicates.

2017-06-17: Registriation of dozens of accounts from a large variety of IP addresses, upload of illegal material and creation of dozens of tasks (see https://phabricator.wikimedia.org/T168142 )

For the records, first "support help desk" spam appearance on this instance in https://phabricator.wikimedia.org/T167009#3380778, from an Indian "Airtel Broadband" IP.

I could, theoretically, write a tool which walks a user's transaction history and systematically reverts every action of the user during a given time period...

More vandalism examples:
https://phabricator.wikimedia.org/p/Ptrpov mass-merged a bunch of tasks on 20171201.
https://phabricator.wikimedia.org/p/FiZie/ on 20171208
https://phabricator.wikimedia.org/p/IZoid/ setting a huge number of parent tasks by editing a single task on 20171209. Related: Could not find a way to fully delete profile images.
https://phabricator.wikimedia.org/p/Sandraramirez3888/ on 20171209.
https://phabricator.wikimedia.org/p/1978Gage2001/ massmoved tasks from one column to another column on 20171211.
https://phabricator.wikimedia.org/p/Popsicleface048/ mass-losing numerous tasks as declined on 20171213
https://phabricator.wikimedia.org/p/ithinker143/ mass-emptying open UBN tasks on 20171214 (same user as https://phabricator.wikimedia.org/p/FiZie/ )

https://phabricator.wikimedia.org/p/238482n375/ - Sweeping changes to a collection of tasks. Biggest impact was setting bugs to secure only and removing subscribers, essentially hiding bugs from projects.

In T84#3592783, @mmodell wrote:

I could, theoretically, write a tool which walks a user's transaction history and systematically reverts every action of the user during a given time period...

Please! That would be fantastic

And now the latest example: https://phabricator.wikimedia.org/p/Vvjjkkii/ - Wrecked several thousand tickets, before they were disabled on 20180630.

At least now the bot is working on reverting (T198552), although it'd be faster if the bot didn't have to wait on the new rate-limits like users do.

What are we missing here? (snuff?)

Probably Comments are OK? Since https://secure.phabricator.com/D8945

Maybe the current issue is with who can use batch edits?

@valerio.bozzolan: What is still missing is covered by this tasks' subtasks (which often are non-public because WP:BEANS).

("snuff" in this case is basically "normal standards" - https://en.wiktionary.org/wiki/up_to_snuff)