Computer viruses are bad enough, but what happens when they start cooperating to ruin your digital life? For months now, authorities and cybersecurity firms have been targeting two strangely named viruses, Vobfus and Beebone. And researchers now think these separate bits of malware have been hard to erase from infected computers because they are working symbiotically to keep each other alive.

Roel Schouwenberg, at cybersecurity firm Kaspersky Lab, says cooperation between computer viruses often signals cooperation among the criminals behind them.

“We know that there are many different cyber criminal groups out there that all have their own trade craft,” he says. “Some of them are good at creating malware, others are much better at infecting machines.”

So hacker #1 builds the program that steals your bank login, while hacker #2 provides him with the program that makes sure the information downloads to your computer.

The good news? Shouwenberg says this example helps anti-virus companies better prepare for future attacks.