Ransomware

Threatens to Take Your Data Hostage

A rise in data kidnappings makes data protection more important than ever. It’s little more than electronic thuggery. Demanding payment for the safe return of your data is one of the newest scams perpetrated by cyber-criminals. And they’re using ransomware – malware that’s expressly designed to encrypt your data – to do it.

In a ransomware attack, the criminal will send the victim an email saying that they have control of their system, and the victim can’t get any data on their system unless they pay the criminal through an untraceable wire service.

In this type of attack, a criminal may put a special file or program in an e-mail and send it to the victim. Or the victim may click on a pop-up window that’s been specially designed to infect the computer with the ransomware. If the victim opens or executes the attachment (or clicks on the pop-up), then the ransom application can encrypt files on the victim’s computer. And the victim can’t open the scrambled files without the key – which the criminal holds. In other instances, the criminals threaten to delete files on the victim’s computer.

The criminal then demands payment, usually with online currency or another wire service. The criminals keep the ransom demands low — $15.99 to $19.00 in order to keep the authorities from getting involved. If they target enough people, they can make a lot of money.

If the victim doesn’t pay, then he or she can’t access the data. Once the ransom is paid, the criminal will supposedly send the key to decrypt the data. But once the victim pays, he or she is now established as willing to pay “protection money.”

How to Protect Yourself

What can you do to protect your company? So far, most of the ransomware attacks have been relatively simple. The ransom applications used symmetric cryptography, which made it possible for security experts to extract the decryption keys from the files without contacting or paying the attackers.

While ransom attacks may be on the rise, you can take steps to protect your users and your business. You can address Ransonware with your existing security protections. Make sure all computers with browsers have the latest patches. Your firewalls, antivirus, intrusion detection and other layers of security protection will likely stop the malware before it infects your network. And do all your backups and keep them offline.

Glossary

Ransomware (malware)

A cryptovirus, cryptotrojan or cryptoworm is a type of malware that encrypts the data belonging to an individual on a computer, demanding a ransom for its restoration. The term ransomware is commonly used to describe such software, although the field known as cryptovirology predates the term “ransomware”.

This type of ransom attack can be accomplished by (for example) attaching a specially crafted file/program to an e-mail message and sending this to the victim. If the victim opens/executes the attachment, the program encrypts a number of files on the victim’s computer. A ransom note is then left behind for the victim. The victim will be unable to open the encrypted files without the correct decryption key. Once the ransom demanded in the ransom note is paid, the cracker may (or may not) send the decryption key, enabling decryption of the “kidnapped” files.

The idea of maliciously encrypting plaintext is not new. The first example is probably the PC Cyborg Trojan that was found in 1989. It encrypted only filenames (using a very weak cipher) causing the file system to be corrupted. There have been other malware attacks that have maliciously encrypted plaintext since then. The 1996 IEEE paper by Young and Yung[1] reviews the malware that has done this, and shows how public key cryptography may be used in such threats.

A cryptovirus, cryptotrojan, or cryptoworm is defined as malware that contains and uses the public key of its author. In cryptoviral extortion, the public key is used to hybrid encrypt the data of the victim and only the private key (which is not in the malware) can be used to recover the data. This is one of a myriad of attacks in the field known as cryptovirology.