Ransomware, a malware that prevents or in some cases limits users from accessing their data has been on the rise. Last year, 2015 saw a considerable increase with Crowti (also known as CryptoWall) and FakeBSOD being the two instances that affected more than 850,000 systems between June and November. In the first quarter of 2015, ransomware saw a 165% increase compared to the previous year. In the second quarter of 2015, 4 million samples of ransomware were identified indicating 58% ransomware growth. Ransomware is expected to grow in 2016 considering that more than half of malware attacks in 2015 also carried ransomware.
The main function of ransomware is to prevent the user (or users if it infects a server) from using that particular system. It does this by encrypting the files that it finds stored in the filesystem and connected drives. Usually, ransomware also tries to prevent certain applications and services from running.
Malicious files
These malicious files are called ransomware because they demand a payment (a ransom) in order to allow the users to decrypt their files; the attacker provides the decryption key in exchange for the payment. Some of these types of malicious files try to convince individuals that they have done something illegal in an attempt to scare them into making the payment (ransomware acting as scareware). In order to be more believable, some ransomware payment demands pretend to be from a law enforcement agency. The ransom usually starts at a few US dollars to hundreds of dollars or its Bitcoin equivalent.
