The "Shellshock" bug, which will reportedly give hackers an access to millions of devices worldwide, has been discovered on Thursday, September 25.

Hackers have started using the "Shellshock" bug in the form of "fast-moving worm viruses," said a report from Reuters.

A report from the Independent said that hackers have already taken advantage of the bug and have posted videos showing the damages they have inflicted online.

The threat, which will reportedly be worse than the "Heartbleed" bug discovered in April, imposed by the virus prompted governments to encrypt their infrastructures.

A report from the New York Times cited the origin of the bug from a free piece of software created in 1987 called Bash. Bourne-Again Shell was reportedly invented by Brian J. Fox and has been used for more than 70 percent of Internet-capable devices, including refrigerators and cameras.

Bash is reportedly used in Apple's Mac operating systems and Linux systems. It is also present in Internet servers.

Security researcher Robert Graham explained the vastness of the bug's reach on his blog, saying: "Internet-of-things devices like video cameras are especially vulnerable because a lot of their software is builty from web-enabled bash scripts. Thus, not only are they less likely to be patched, they are more likely to expose the vulnerability to the outside world."

The newly discovered bug has been compared with "Heartbleed," which could be used to acquire personal information such as passwords, but reports say that it could cause more damage as it has the ability to penetrate an entire machine and take over it.

Experts also reportedly found it relatively easier to trace "Heartbleed," as it was discovered two years after it started spreading. The Shellshock bug, however, has reportedly existed for 22 years before experts found it.

The bug was discovered by experts from open source software company Red Hat after they found several problems with their servers.