Question

Technique used by an attacker to gain access to another device may be broadly termed as

Answer 1

it is called cyber attack

Answer 2

Cyber attack or Cyber hacking is answer.

Cyber attack is performed in many different ways. Important ways include the attempt of sending phishing emails that has malicious links or corrupted attachment which upon accessing steals the information, hacking the computer system using a malware and gain access to the targeted computer, etc.

Hope it helps.