For years, ransomware actors have developed new families and attack campaigns in increasing frequency and numbers. Such activity peaked in 2017 but then fell in tandem with cryptocurrency miners’ rise. This development was short-lived, however. Between Q4 2018 and Q1 2019, Malwarebytes observed a 195 percent increase in ransomware detections involving business targets. The rate was even greater compared to Q1 2018 at 500 percent.

Ransomware attacks of varying significance made news over that multi-year period. Here are 10 of the most significant of those attacks. (For the purposes of this article, “most significant” does not account only for the number of users affected. It also takes into account other factors such as distribution, costs, updates, media coverage and potential damages for future victims.)

Hollywood Presbyterian Medical Center

In February 2016, Hollywood Presbyterian Medical Center temporarily suspended its IT system after detecting suspicious activity. The southern California medical center subsequently shut down several departments and diverted patients to other institutions for treatment while staff recorded registrations/logins via paper and fax. A few days later, the hospital revealed that ransomware had affected its systems; Hollywood Presbyterian Medical Center ultimately paid the ransom of 40 bitcoins (then worth $17,000) after working with law enforcement.

San Francisco MTA

Later in 2016, ransomware attackers targeted 2,000 computers owned by San Francisco’s transport system (known as Muni). This incident didn’t disrupt the system’s rail and bus network, but it did affect Windows workstations, servers and ticketing machines. As a result, many passengers enjoyed free rides on Muni’s trains and buses while IT personnel worked to recover from the attack. These individuals’ efforts revealed that a strain of HDDCrypter had struck the transport agency and had demanded 100 bitcoins ($70,000) in ransom.

WannaCry Outbreak

On 12 May 2017, an updated version of WCry/WannaCry ransomware (Read more...)