This hunter of games demands real ransom

MUMBAI, INDIA: Kaspersky Lab has detected curious behavior in a new threat from the TeslaCrypt ransomware encryptor family.

Most TeslaCrypt infections occur in the USA, Germany and Spain; followed by Italy, France and United Kingdom.

Early samples of TeslaCrypt were detected in February 2015 and the new ransomware Trojan gained immediate notoriety as a menace to computer gamers. Amongst other types of target files, it tries to infect typical gaming files: game saves, user profiles, recoded replays etc. That said, TeslaCrypt does not encrypt files that are larger than 268 MB.

The Trojan:

In version 2.0 of the Trojan notorious for infecting computer gamers, it displays an HTML page in the Web browser which is an exact copy of CryptoWall 3.0, another notorious ransomware program. Perhaps the criminals are doing this as a statement of intent: so far, many files encrypted by CryptoWall could not be decrypted, which is not the case with many past cases of TeslaCrypt infection. After a successful infection, the malicious program demands a $500 ransom for the decryption key; if the victim delays, the ransom doubles.

How it works?

When TeslaCrypt infects a new victim, it generates a new unique Bitcoin address to receive the victim’s ransom payment and a secret key to withdraw it. TeslaCrypt’s C&C servers are located in the Tor network. The Trojan’s version 2.0 uses two sets of keys: one set is unique within one infected system, the other is generated repeatedly each time the malicious program is re-launched in the system. Moreover, the secret key with which user files get encrypted is not saved on the hard drive, which makes the process of decrypting the user files significantly more complicated.

Programs from TeslaCrypt malware family were observed to propagate via the Angler, Sweet Orange and Nuclear exploit kits. Under this malware propagation mechanism, the victim visits an infected web site and the exploit’s malicious code uses browser vulnerabilities, most typically in plugins, to install the dedicated malware on the target computer.

TeslaCrypt, a hunter of gamers, is designed to deceive and intimidate users. For example, its previous version displayed a message to the victim saying that his/her files were encrypted with the famous RSA-2048 encryption algorithm, and thus demonstrated there was no option to paying the ransom. In reality, the cybercriminals did not use this algorithm. In its latest modification, TeslaCrypt convinces victims they are dealing with CryptoWall – once the latter encrypts user files there is no way to have them decrypted. However all links lead to a TeslaCrypt server – apparently, the malware authors have no intention of giving their victims’ money away to a competitor,” said Fedor Sinitsyn, Senior Malware Analyst, Kaspersky Lab.

Recommendations:

Create back-up copies of all your important files on a regular basis. Copies should be kept on media that are physically disconnected immediately after the backup copying is completed.

It is important to update your software in a timely fashion, especially the Web browser and its plugins.

According to Altaf Halde, Managing Director, South Asia, Kaspersky Lab, "Ransomware is a type of malware that is a digital mechanism for extortion. It is a type of software to block access to a computer system until a ransom is paid or to user or company data or both. CryptoLocker, CryptoWall, CoinVault, TorLocker, CoinVault and CTB-Locker are all examples of ransomware.”

A ransomware attack is typically delivered via an email that includes an attachment that could be an executable file, an archive or an image. Once the attachment is opened, the malware is deployed on the user’s system. A key motivation for cybercriminals executing a ransomware attack is to extort money from victims; however, security companies are seeing that the average case of a ransomware attack against a business is quite damaging given that the target of an attack is typically the company’s intellectual property.