rootkit

noun

1. A set of software tools used by a third party to gain unauthorized access to a computer system and control the system while concealing itself from the user.

verb

1. (transitive)To infect (a computer system) with a rootkit.

   “Given crackers' propensity for "rootkitting" systems — installing altered system binaries to facilitate future access — systematic integrity checks using message digest algorithms or one-way hash functions can be an important detection safeguard.”

   “If not, your system might have been rootkitted.”