Keeping the fact in mind that network access has been found to be slow and after questioning the employees, the network administrator learns that an employee downloaded a third-party application which turns out to be a scanning program for the printer.
Explanation:
The employee must have been unaware of the fact that the application was accompanied by a worm or a computer worm.
A computer worm is a type of malware that has a property to replicate itself and after infecting a particular computer increases its range and gets in the other computers working on the same network which is the main reason for reduced processing speed.