Ransomware has been around for years, but has seen a rapid rise to the popular mainstream in the last couple of months. Ransomware is generally seen as a type of malware that restricts access to the computer or device it infects, not releasing control until some sort of monetary payment has been extracted.
The malware can generally operate at the boot or pre-OS level, encrypting the underlying files, photos and music that the user deems so important. This encryption process is managed by the malware, with the contents not being decrypted until either a bank transfer, SMS or premium rate phone call is made to the malware operator. Other basic ransomware payloads, simply restrict access to the main interfaces of the operating system. So instead of encrypting the contents, access to things like explorer.exe in Windows or the command line shell are prevented, making the machine practically useless.
The main theme behind ransomware is illusionary, with situations often using sophisticated framing and social engineering techniques. Recent ransomware attempts have included the malware giving the impression that the victim has been caught by a law enforcement agency, for perhaps downloading pirated software or music. The computer is then 'locked' by the malware with a message indicating that a fine requires paying before the machine can be released. This type of advanced social engineering attack is becoming so popular that the US's federal Internet Crime Complaint Centre, released a public advisory, explaining that any 'official' looking messages or locking of machines is fake and not from the FBI.
Even this week another attack was seen in Australia, with a malware claiming to be from the Australian Federal Police.
Most infections occur via the standard virus and worm proliferation vectors - tainted websites and links, or attachments. The sophistication of such attacks is based on the social engineering that takes place. Server side collectors, are localised to the victims country, with near perfect looking imagery, wording and local language and nuances. The main driver for such a complex back office is monetary reward.
Wide spread virus attacks are no longer the result of script-kiddies and political activists. It's big business. A malware attack on just a particular country or even city can rake in $50-60k a day before being tracked down.
The main factors for protection are pretty much the same for any other virus or worm. Antivirus needs to be running and updated regularly. Be careful opening attachments from unknown sources or contain unlikely subject lines. URL's and links should be pre-scanned using whatever browser plugin you use. More importantly, which should be second nature anyway, is to make sure any essential data on your laptop or PC's is backed up remotely. If worst comes to the worst, a simple OS reinstall, flattening the boot partition can quickly get you back to time-0.