Virus infected files
One sure way of losing valuable data from your computer is if it becomes infected by a computer virus. In order to avoid detection by users, some viruses use different kinds of deception. Some old viruses, especially on the MS-DOS platform, make sure that the "last modified" date of a host file stays the same when the virus infects the file. This approach does not fool anti-virus software, however, especially those that maintain and date cyclic redundancy checks on file changes.
Virus infected files are usually slightly larger than before infection, however some viruses can infect files without increasing their sizes or damaging the files. They do this by overwriting unused areas of executable files. These are called cavity viruses. Virus infected files should be deleted or placed in quarantine by anti-virus software.
As computers and operating systems grow larger and more complex, old hiding techniques need to be updated or replaced. Defending a computer against viruses may demand that a file system migrate towards detailed and explicit permission for every kind of file access.
Virus infected files can cause a computer to hang, and a subsequent hard reboot will render a system restore point from the same day corrupt. Restore points from previous days should work provided the virus is not designed to corrupt the restore files or also exists in previous restore points. Some viruses, however, disable system restore and other important tools such as Task Manager and Command Prompt and it may not be possible to restore the system. If you suspect that you may have virus infected files on your computer and you’re not sure how to remove the virus and restore the system to normal, contact Intratec for assistance.
|
