Means the same thing as a malicious hacker (in today's computer/cyber society). Cyber spies are very dangerous, as they can perform sabotage to another country's systems, as well as perform espionage to steal information off of government databases.
Hunting down cyber spies are much harder than ordinary spies, especially when they're in a foreign country.
A Russian Hacker (Cyber Spy), breaks into a very important U.S. Database to obtain military, defense, and other secrets.