I am looking at the code.
I think it may have something to do with the third parameter of SendChatMessage(). If left nil means that the message will be translated to the default race language.

This explains 2 things:
1) Why some people dont get disconnect (maybe your character was of the same race as the attackers, unlike your girlfriend's)
2) Why it doesnt work on opposing faction players.

Edit:

On further examination, I think we can understand how this exploits works if we look at its fix:
SET readContest "-1"
SET readScanning "-1"
SET spamFilter "0"
SET profanityFilter "0"
Now, I dont know what readContest or readScanning do. However, its possible that *maybe* the text of the message (which is hardcoded in the mod) translates into Orcish (or any other language) in such a way that it triggers the profanity filter, and or the spamfilter.
Interesting.

We're both human. It doesn't work on opposite faction because you can't type to them in the first place.

Same race, same class.

But how did it happen to your whole raid group at once (or, well, half of them), unless it was someone inside your raid doing it? Can it be done through Naxx General or the like?

It can be done to any of these groups:
http://www.wowwiki.com/ChatTypeId

(yes, that includes /1 /2 ... falls under "CHANNEL" category)

Then General and LocalDefense seem like the likeliest culprits, unless someone inside your raid actively wanted you to wipe on 4H.... Did you ask others in the zone with you at the time?

It's probably done using the same method that lets level 1 advertisers for gold selling sites broadcast into general chat of other zones from their creation point.

Man I hate that trick. The first time it happened, I said something on Vent to the effect of "now that's dedicated, getting an account attuned with BWL just to spam us a couple of times knowing it will be reported and banned within a day", and promptly got laughed at by everyone else who had bothered to check that it was being done by a level 1 orc in durotar :(

damn this happened to me and several other yesterday in our raid too. Wasted over about 45 mins of our time as 30-35 people had to watch the other 5-10 continuously crash. Hell I deleted and reinstalled and reconfiged all my addons because of this...

Good to know there is a quick fix though, making sure every person in the raid has the fix applied now.

some of my mates got this one yesterday.
everytime he tried to log on his character he got disconnected. deleting the wtb/wtf/addons folder helped out so that he could log in again.

I think I've done this to my raid before, I had a mod that would say in a particular channel a famous quote which was very harmless, every time I used the mod after the patch which introduced the hidden channels my raid would crash, luckily it was only in ZG before I ditched it, it made absolutely no sense at all.

About a year ago we were doing nef and just before phase 3 our heavily glorifyed and known MT and OT both get disconnected and begin sitting.

Needless to say our MT was healed through 5% while sitting and he kept aggro for 10% at least.

With the joy of fear ward we had our MT offline tank onyxia from 10% to zero :)

I haven't seen the exploit code, or witnessed it myself, but I'm guessing that what happens is that a certain string will be caught be the profanity/spam filter, and the output from the filter will be something that the filter triggers on again (and again, infinitely), so basically the filter will keep invoking itself, and this will lead to a "stack overflow" (the stack is a chunk of memory used to store data when a function calls another function).

That seems reasonable. At very least, after looking at the mod, the conclusion seems to be that certain incoming strings simply crash the client, depending on settings. The mod doesn't do anything interesting at all.

Now why would that string be picked up by the profanity filter in the first place? And what the heck is the "spam filter"?

I don't have access to the code, but I'm curious (and also a coder who have done a few mods) (*subliminal hint*). :)

However, argument 3 to SendChatMessage can (and should really) be nil. It means the message is sent in your faction default language, ie "common" for Alliance players and "Orcish" for Horde players. It's very common to leave the third argument nil.

And you can see other faction languages, I'm almost sure at least. But it's a lot of gibberish, more so than usual. Anyway, if it uses an ingame channel there's no point as alliance and horde channels are never shared. :)

.

Ahh, that makes sense. I figured the mod had to be doing something nontrivial, or it wouldn't exist.

Heh sounds a bit like what used to happen quite regularly in EQ.

A rival guild sending all of the other guild's clerics a certain tell with specific text that immediately crashed them. It went on for quite awhile before a fix was found iirc, but the players doing the crashing weren't even reprimanded.

Crashing is freaking annoying as is; I'd be doubly pissed if someone did it purposefully.

Things like this make me glad I join only guild channels upon log-in.

I actually had all 4 lines in my config file already. Now i'm trying to figure out what options or mods would have put them all in there in the first place.

EQ was coded so poorly. It was not even clever at all like this exploit. You could just spam someone "|||||||||||||||||||||||||||||" and it would crash them for sure if they were running at native resolution. EQ had like a really small pixel width for the pipe character '|' and the client had some hard coding on what it expected widths of strings to be so when your client tried to draw the string you would just shut down.

Yea I was never actually sure what the text was, I just recall a pretty big thing when I think the guild was on The Idol in Kael and actually was having a good run and everyone got bumped.

I find it pretty amazing the things people will go to to destroy someone else's gameplay.