Companion virus is a malicious computer program, similar to a worm, that is most destructive when it attaches itself to an executable file on a computer system. It works by making a copy of itself and then renaming the original file to a different name. The copy is then repaired with malicious code which can be used to spread the virus onto other files or networks.
Unlike traditional viruses, companion viruses do not require the user to open an attachment or click a link in order to be activated. Instead, they are triggered when the user runs one of the malicious rewrite files. This causes an additional malicious process to be executed, which can then spread the virus to other files, or in some cases, to other computers on a network.
Companion viruses are classified as file infectors. They are generally spread via USB stick, email attachments, fake software updates or system downloads. It is important to note that the virus will not typically spread if the file it attached itself to is not executed.
Although companion viruses are often overlooked by antivirus software, they can cause significant damage to a computer system. Common symptoms of a companion virus include sluggish performance, altered system settings, and the presence of suspicious files and programs. In addition, the virus may cause files to become deleted or corrupted unexpectedly.
To protect against companion viruses, users should take precautions to ensure that their computer is regularly scanned and updated with the latest antivirus and malware protection. Additionally, users should be careful of any suspicious emails they receive or links they click, which could be part of an attack.
