Someone rooted my box and executed a command, help!
dd if=/dev/urandom of=.huehuehue
what does this command do?
As others have said it fills up a file with random data.
You might ask, well, why would an attacker want to do that?
The likely reason is that, by using up all the space on the disk, it will overwrite any blocks containing data from deleted files, which may cover their tracks.
Taken together, the command means to copy content from the input file, in this instance
I don't think this is a question particularly related to Ubuntu, personally, but it was asked here. Maybe this should be shifted to unix ?
You might also want to try running
I hope there was no other damage if this was a genuine case.
That fills up your file system by reading from a pseudo-random number generator and outputting it to a file named ".huehuehue". It's hilarious.
It's probably done running by now. Just delete the file.
If your box got rooted, you're going to want to wipe the drives and re-install. It takes longer to do the forensic work to prove they haven't added in some rootkit or timebomb that it does to just re-install.