Countdown. Five minutes left.
Green, orange, and red lights blinked on a panel, indicating the streams of information flowing through the multitude of cables attached to it.
The router repelled the attacks, discarding tens of thousands of packets per second, blocking addresses, fending off fragments intended to clog up the system. It fought desperately and tirelessly. At that moment It didn't make any difference. A string of bytes, small like a single cell of HIV, slid inside, enveloped in layers of code indicating a normal and harmless HTTP response. A web page requested by some bored and procrastinating employee.
The page with the disease reached the browser, and the browser started picking it apart, converting it into visuals. At some point, it reached this strange string of bytes and slightly puzzled pushed it into its stack trying to figure out what it was. In the next nanosecond, the browser observed with a horror how this string suddenly inflated into something big and disgusting like a tapeworm, weaving coils upon coils of its body, damaging everything around. The browser choked with this bloated, pulsing mass and crushed.
A nanosecond before browser's death the worm took full control of its brain and manipulating it as a zombie ordered it to embed it into the root process. During the seconds while the unfortunate employee wondered what happened to the browser and tried to reload it, the worm spread throughout the whole network taking control. Antivirus systems were shutting down everywhere complying with the orders of the root process controlled by the worm.
Opening already damaged gates wider, the worm pulled in the gigantic brain of the main program and put it in charge. The monster woke up and got to work, methodically checking the openings and weak spots in the network. It didn't hurry. Now and then it made pauses to keep the central anti-malware systems from raising the alarm. When it found the critical opening on the mail server in the form of a decade old vulnerability that IT team neglected to patch, everything in the network still looked as usual. The antivirus programs showed green status, everything safe and clear. Nobody had been aware yet that those programs were already under worm's control, and that the network was swarming with vicious tentacles; infected packets and reconnaissance units examining the entry points of the key servers.
The mail server had a small imperceptible hole in its defenses. An old and doddering program, some ancient messenger whose existence had been forgotten by everybody long ago. For the first time after fifteen years of slumber, the messenger heard somebody calling for him. He woke up cheerfully to receive the package. He was pulling it in when he realized that it was too big to fit, but the package kept pushing itself inside, brutally squashing the messenger's senile body. Before screaming and passing out the messenger performed its last command. The worm proudly emerged in the system as a privileged process, not restricted by anything or anybody. It unhurriedly took over all the administrative accounts and spread itself to the other servers around the network. The anti-malware programs were choked before they could raise an alarm. For anybody looking at the computer screens, everything still looked as usual.
Now wearing the credentials of the domain administrator the worm entered the central domain servers. It didn't need to conceal its intentions at this point. It marched in openly, slashing the throats of anti-viruses. To its frustration, a part of the network controlling the nuclear facilities was separated by a gateway bristling with defenses and under the separate chain of command. They didn't recognize worm's authority there. It was time to pass the controls to the human.