South Korea's largest cryptocurrency exchange, Upbit, has disclosed that it was targeted by hackers over 159,000 times in the first half of 2023, a 117% increase from the same period in 2022. This is a sign that cryptocurrency exchanges are increasingly being targeted by hackers, as they hold large amounts of valuable digital assets. The most common types of hacking attempts against Upbit were phishing attacks, brute force attacks, and denial-of-service (DoS) attacks. Phishing attacks attempt to trick users into revealing their personal information, such as their passwords and two-factor authentication codes. Brute force attacks involve trying to guess users' passwords using a computer program. DoS attacks attempt to overwhelm a website or server with traffic, making it unavailable to legitimate users.