Researchers at Anomali have spotted a new ransomware strain that is targeting users of QNAP Systems' network-attached storage (NAS) devices.
The operators of the malware appear to be gaining access to the devices either by brute-forcing weak credentials or by exploiting known vulnerabilities in them. However, the exact infection vector remains unclear for the moment, the security vendor said in an advisory released Wednesday.
The ransomware, dubbed eCh0raix, seems designed for targeted attacks and not just for mass distribution. Hard-coded encryption keys in some samples of the malware that Anomali analyzed appeared to have unique decryption keys associated with them, meaning the same decryptor would not work for all victims.
Taiwan-based QNAP is a relatively major player in the NAS market worldwide.
"We have seen a fully 'offline' version and a version that reaches out to the C2 server to fetch the bitcoin wallet and public key before it starts," says Joakim Kennedy, threat intelligence manager at Anomali.
The online version alerts its command-and-control server when it starts and finishes encrypting files on an infected device. However, the information that is sent back to the C2 server does not contain any tracking data that would reveal the identity of the victim to the attacker.
The offline version, on the other hand, has the encryption information embedded in the malware and seems compiled for specific targets. The hard-coded public key in these samples is used to encrypt the AES key that encrypts and decrypts the files, Kennedy says.
eCh0raix is the latest example of ransomware being used in targeted attacks. Numerous security vendors have reported a substantial decline in general ransomware activity in the last few months. However, at the same time, there has been a sharp increase in attacks targeting enterprise organizations.
In its "2019 Internet Security Threat Report," Symantec noted ransomware infections on endpoints dropping by 20% in 2018 compared with the year before — the first drop in volume since 2013. Significantly, though, 81% of all ransomware infections last year involved enterprises — a sharp reversal from a few years ago when consumers were the primary targets.
Poorly Protected Systems
With eCh0raix, the threat actor behind it is targeting QNAP NAS devices that people use for backups and file storage purposes. Such devices typically do not run antivirus or anti-malware products, which means eCH0raix is able to run on them with little risk of being detected. The samples that Anomali analyzed were detected by just two or three anti-malware tools on VirusTotal, Anomali said.
It's unclear if the operators of eCh0raix are targeting older QNAP devices or more recent ones, but it is likely they are scanning the Internet for accessible devices. Based on Anomali's own Internet-wide scans, there appears to be currently over 19,000 publicly facing QNAP devices in the US. It's unclear how many of these devices are deployed in enterprise organizations, Kennedy says.
What makes the malware interesting is that it is targeting NAS devices, Kennedy notes. Besides having relatively little protection, such devices are usually used to store important files and backups especially in enterprise settings. Therefore, NAS devices present a potentially lucrative target for ransomware authors, he says.
Some victims of the malware have reported seeing a high number of failed login attempts just before being infected, suggesting a brute-force credential attack. Others have reported their systems as not being fully patched, suggesting the attackers may be exploiting vulnerabilities on QNAP NAS devices.
From a technical standpoint, eCh0raix is a fairly basic ransomware tool written in the Go programming language. Before the malware executes, it kills off several processes on the infected machine and looks for certain files to avoid, such as /boot/, /proc/, /sys/, /run/, and /dev/, Anomali said. It then looks for and encrypts all data, image, media, and memory dump-related files on the system.
The malware is another reminder for enterprises to lock down all their Internet-facing assets, Kennedy says. "Organizations should perform asset management and ensure that only necessary devices are publicly facing," he says. "Strong login credentials should be used and systems should be kept updated with the latest patches to ensure that exploitation is less likely."