What are some sophisticated kinds of spyware that are used by intelligence agencies?

There are lots of advanced kinds of spyware used by intelligence agencies. A few of these consist of keyloggers, which record every keystroke made by a user; remote access tools, which enable an attacker to acquire control of a victim's device; and malware that is developed to take delicate data or passwords.

One particularly advanced type of spyware is called a rootkit. Rootkits are created to conceal themselves from detection, and can be really hard to remove when they have been installed on a system.  https://scarabnet.org/?p=338 They are typically used to give an enemy complete control of a victim's machine, enabling them to spy on the user, or even take control of the device remotely.

https://creaturesincrisis.org/?p=638 Another advanced kind of spyware is referred to as a botnet. A botnet is a network of contaminated computer systems that can be controlled from another location by an assaulter. Botnets can be utilized to introduce distributed rejection of service (DDoS) attacks, or to send out spam and phishing e-mails. They can likewise be used to spy on users, or to take sensitive data.

Spyware is becoming progressively advanced, and intelligence companies are constantly progressing their techniques and tools to stay up to date with the latest dangers.