VTTEST and MOZILAVT HTTP methods, what are these?

Question

I got several alerts in the last two days bcs our service responded 5xx in a large percentage of the requests (tipically offhours when we have zero to low traffic anyway).

When I checked the application logs I found these two;

Illegal request, responding with status ‘501 Not Implemented’: Unsupported HTTP method: MOZILLAVT

Illegal request, responding with status ‘501 Not Implemented’: Unsupported HTTP method: VTTEST

Any idea what are these, and which tools produce them? Google not helped.

It is clear that our site is under some kind of vulnerability testing, as I see the nginx access logs, but these requests are not there, which is even stranger.

Inquiring

No one knows? :-o I am also seeing these today, along with "TRAK" requests. Google doesn't return anything useful. – Elinoreeliot

Answer 1

Not a real answer here, but I found leftovers with that string "MozillaVT" from an U.S. IP that made 21 thousand requests in a 10h time lapse. Blocked the IP but I wonder what tool is this.

Skimmer