A stealth virus is a kind of malware that does everything to avoid detection by antivirus or antimalware. It can hide in legitimate files, boot sectors, and partitions without alerting the system or user about its presence. Once inside a computer, a stealth virus allows an attacker to take over the functions of the infected computer.

A stealth virus is like a rebel who wears a camouflage suit to remain unidentifiable among soldiers. He or she can then pretend to be one of the good guys to infiltrate a target.

Other interesting terms…

Read More about a “Stealth Virus”

In general, antivirus or antimalware solutions fail to detect a stealth virus because it is relatively new. At other times, the system user has yet to update his or her antivirus or antimalware to detect it.

Detecting and removing the virus from an infected computer can be tricky. It requires sophisticated antivirus or antimalware. Some computers might need a complete system reboot or reformat. Learning how a stealth virus gets into systems, though, can help reduce risks.

How Can a Stealth Virus Infect a Computer?

A stealth virus can affect a system via:

  • Code modification: A stealth virus can change computer settings so the attacker can control the system without the user’s knowledge. It modifies code to cover its tracks.
  • Data encryption: A stealth virus can also encrypt data, making files inaccessible to or unreadable for the computer owner.

A stealth virus is designed to remain undetected. Some stealth viruses hide within legitimate files without changing their size so they can evade detection. Others self-destruct after execution. And still, others change locations after encrypting target files.

How Can Users Protect against a Stealth Virus?

A stealth virus that has successfully infiltrated a computer can only be detected after a disk boot. You can do that by starting your system from a removable disk such as a universal serial bus (USB) drive set to be read before the computer’s hard drive. That way, even if the virus has complete control over the system, it can’t run before your antivirus or antimalware.

Once detected, remove the virus, including its copies, from your computer. This process is complicated, so you may need an expert’s help. That said, the best way to avoid stealth viruses is to prevent them from infecting your system with the help of advanced security software that’s always updated.

It is also best to adhere to security best practices, such as never opening spam and clicking suspicious links.

Trivia

Did you know that the first Disk Operating System (DOS) virus Brain is a stealth virus? Brain was discovered way back in January 1986. It is classified as a system infector. It monitors a computer’s physical disks. Every time an attempt is made to discover it, Brain points the system to read an uninfected boot sector instead. It’s much like throwing a stone to make a sound somewhere else so a person looking for you won’t discover your hiding place.