Kaspersky researchers have identified a new type of ransomware attack which is actively growing in popularity,
targeting network attached storage (NAS) and posing new risks for back-up data.

With NAS largely perceived as a secure technology, users often remain unprepared for the possibility of infection, putting their data at higher risk.

Encryption ransomware is a malware that applies advanced encryption methods so files cannot be decrypted without a unique key.

This leaves the infected device owner stuck with a locked device and a demand to pay a ransom in order to regain access to files.

While users are typically infected with ransomware via email or exploit-kits planted on websites, the new type of attacks on NAS devices use a different vector.

Ransomware operators scan ranges of IP addresses looking for NAS devices accessible via the web.

Although only web interfaces protected with authentication are accessible, a number of devices have integrated software with vulnerabilities in it. This allows the attackers to install a Trojan using exploits, which will then encrypt all data on the devices connected to the NAS.

“Previously, encryption ransomware targeting NAS was hardly evident in the wild, but this year alone we have already detected a number of new ransomware families focused solely on NAS,” says Fedor Sinitsyn, security researcher at Kaspersky.

“This trend is unlikely to fade, as this attack vector proves to be very profitable for the attackers, especially due to the users being completely unprepared for them as they consider this technology highly reliable.

“NAS devices are usually purchased as complete and secure products, which as it turns out is not the case. Consumers and especially business users need to therefore remain cautious when protecting their data,” he adds.

During Q3 2019, Kaspersky products detected and repelled encryption ransomware attacks on 229 643 Kaspersky products users, which is 11% less than during the same period last year.

Although the total number of affected users slightly decreased, the report shows that the number of new encryption ransomware modifications grew from 5 195 in Q3 2018 to 13 138 in Q3 2019 marking 153% growth.

This development signals cybercriminal interest in this type of malware as means of enrichment.

At the same time, the infamous WannaCry Trojan family retained first place among the most popular Trojans with over a fifth of attacked users having been targeted with malware identified as belonging to this group.

The top three most popular verdicts that account for almost half of users attacked by cryptors were Trojan-Ransom.Win32.Wanna (20,96% users attacked), Trojan-Ransom.Win32.Phny (20,01%) and Trojan-Ransom.Win32.GandCrypt (8,58%).