its a generic file, just google for it, you will find many sources. Its part of a root kit. You have to analyse your server log files to find out from where it comes. I guess it comes from brasilia ....
You can do nothing.
Erase this file, check the server for any kind of rootkit, dont allow the excution of scripts from the /tmp folder, apply any php patch (5.1.4 is actual) turn globals of and check any script running on your server for updates.
There are many scripts out there with security holes. I found a gallerie script on my server with possble XSS holes. Threads closed many holes and I continue my checks.
Watch your server error log file frequently
