First the good news. In November 2015, Kaspersky announced the ransomware variants Coinvault and Bitcryptor were dead. The alleged authors were arrested and all 14,000 decryption keys were released. But as we mentioned in our blog “Cyber Security Predictions for 2016”, ransomware is an increasing menace. That is because it is a big moneymaker for cybercriminals. The malware uses strong encryption to prevent users from recovering files unless they pay a ransom. Be warned: even if you pay, the attackers may or may not deliver a valid key to unlock your files!
A recent trend is a threat to post user data and photos online unless the ransom is paid. This has been seen most often with Chimera ransomware. Most security analysts think this is simply a scare tactic. Here’s why:
In the past ransomware largely affected Windows-based devices. But Linux devices are a tempting target because a large number of servers use Linux. Not only can servers be victims; they can be used to further distribute the malware to other devices. As of November 2015, Malwarebytes reported a new variant of Linux ransomware, bringing the total to four. The new ransomware demands up to $999 for any victim who is not a citizen of Russia and the Commonwealth of Independent States.
This malware first appeared in 2013. In May 2014, a combination of law enforcement agencies and security companies seized a worldwide network of hijacked home computers that was being used to spread Cryptolocker. While the cybercriminals were transmitting their key database for backup, the authorities intercepted it. As a result, all 500,000 victims of Cryptolocker can now recover CryptoLocker-encrypted files without paying a ransom.
An interesting aside: The original CryptoLocker continues to claim new victims. Early in 2015, American Electric Power , the largest power grid operator in the US, was infected when a supervisor opened a personal email on a company laptop. In addition, since November 2015, there is also CryptoLocker Service. This scheme has lowered the expense of a ransomware campaign by charging $50 plus a ten percent commission on each ransom paid plus a fee for payload customization. Although the developer also calls the software CryptoLocker, he says it is completely different from the older software.
Based on several IT forum conversations many small and medium-sized businesses experienced mainly CryptoWall and TorrentLocker ransomware attacks in the fall of 2015. TorrentLocker is known for spear phishing from purported delivery services and utilities. In Australia, spear phishes referred to bogus speeding fines sent by the Australian Federal Police. TorrentLocker targets individuals as well as businesses.
Curve-Tor-Bitcoin (CTB) Locker is spread via a bulk spam campaign instead of spear phishing. Unlike most other ransomware, it does not require an active internet connection before it starts encrypting files. A unique feature is a reliance on Elliptic Curve Cryptography (ECC), requiring a significantly smaller key size compared with RSA encryption. Attackers use the ransomware to recruit CTB Locker “affiliates” from their victims, accelerating dissemination of the malware.
TeslaCrypt appears to be a derivative of the original Cryptolocker ransomware. It is reported to have had the largest number of infections seen widely across all countries, second only to CryptoWall. Most infections are spread by phishing / spam emails. TeslaCrypt, like many ransomware types, obscures code to evade detection.
Stay tuned......In Part 2 of this series to be published on Wednesday, we examine the relative newcomer Chimera and the big daddy of ransomware, CryptoWall. Then we tackle the important question of how to protect yourself from ransomware.
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