Ransomware Attacks Now Targeting Your Backups

Ransomware Attacks Now Targeting Your Backups

Backups have traditionally been regarded as the last line of defence against ransomware attacks. Over the past few months, however, backups have been specifically targeted by ransomware attacks.

In the "IT threat evolution Q3 2019" report, Kaspersky researchers found that ransomware attacks on backups, specifically NAS backups, are gaining ground.

What Is NAS?

NAS, short for network attached storage, is a storage and backup system that consists of one or more hard drives. This storage and backup system can be connected to home or office network or the internet. In case a NAS device is connected to the internet, data stored on this device can be accessed using a web browser or mobile app.

Ransomware Targeting NAS

Researchers at Anomali in July of this year reported about eCh0raix, a ransomware that specifically targets QNAP network attached storage (NAS) devices. According to the researchers, the source code of eCh0raix has less than 400 lines, with functionalities that are typical to a ransomware, including checking if data in the infected system has already been encrypted, going through the file system for files to encrypt, encrypting the files, and producing the ransom note.

Researchers at Anomali noted that eCh0raix ransomware isn’t designed for mass distribution as the samples with a hardcoded public key appear to be compiled for the target with a unique key for each target.QNAP Systems, the manufacturer of QNAP network attached storage (NAS) devices, for its part, acknowledged that QNAP devices using weak passwords and outdated QTS firmware are vulnerable to eCh0raixransomware.

In July of this year, another NAS device manufacturer Synologyreported that several of Synology NAS devices were under ransomware attacks as a result of brute-forcing administrator login details. In a brute-force attack, a malicious actor submits a number of passwords in the hope of eventually guessing the correct one.

According to Synology, its investigation related to the ransomware attacks found that the attacks were due to dictionary attacks – the use of words in the dictionary in brute-forcing login details – instead of specific system vulnerabilities. Synology added that the large-scale ransomware attacks were targeted at various NAS models from different NAS vendors. Ken Lee, Manager of Security Incident Response Team at Synology, said that NAS attackers used “botnet addresses to hide their real source IP”.

Just last month, another NAS device manufacturer D-Linkacknowledged that the following D-Link network attached storage (NAS) models are vulnerable to a different ransomware called “Cr1ptT0r” ransomware: DNS-320 Ax/Bx, DNS-325, DNS-320L, DNS-327L, DNS-323 Ax/Bx/Cx, DNS-345, DNS-343 and DNS-340L. According to D-Link, Cr1ptT0r encrypts stored information and then demands payment to decrypt the information.

According to Kaspersky researchers, the growing ransomware attacks on NAS devices involve attackers scanning the internet for internet-connected NAS devices. Kaspersky researchers said that a number of NAS devices have vulnerabilities in the firmware, which enables attackers via an exploit to install on the compromised device a Trojan – a type of malicious software (malware) that’s often disguised as legitimate software – that encrypts all data on the NAS device. “This is a particularly dangerous attack, since in many cases the NAS is used to store backups, and such devices are generally perceived by their owners as a reliable means of storage, and the mere possibility of an infection can come as a shock,” Kaspersky researchers said.

Preventive and Mitigating Measures

Here are some of the preventive and mitigating measures against ransomware attacks targeting NAS backups:

1. Use Up-to-Date Backup Device

Manufacturers of NAS devices, QNAP Systems, Synology and D-Link, asked users to apply the latest software or firmware version.

In the case of D-Link NAS devices, D-Link said that DNS-320 Ax/Bx, DNS-323 Ax/Bx, DNS-325 Ax and DNS-345 Ax have passed their end of service date, which means that these models are no longer supported by the company through customer support and no longer receive software or firmware updates. For the said models that have passed their end of service date, D-Link asked users to "remove the Internet access of NAS on your router by disabling the port forwarding and DMZ setting".

2. Keep Backups Offline

One thing is common to these NAS ransomware attacks: They victimized only those devices that are connected to the internet. To protect backups from this type of ransomware, it’s important to disable internet connection to these devices.

3. Harden Defences If the Backup Needs to be Connected to the Internet

Generally, an internet-connected NAS device can only be accessed via a web or mobile app interface and this interface is protected by an authentication page, where a user has to authenticate oneself before logging in. As acknowledged by NAS manufacturers, some users use weak passwords, making it easy for attackers to brute-force or guess the passwords.

When there’s a need for these NAS devices to be accessible via the internet, it’s important to use strong passwords and, if possible, to use multi-factor authentication to add another layer of defence.

4. Additional Defences

Here are some of the additional defences to protect backups from ransomware attacks:

• Disable SSH and Telnet services if they aren’t use
• Avoid using default port numbers 443 and 8080
• Enable Auto Block to block IP addresses with too many failed login attempts
• Use Firewall

As shown in the number of ransomware attacks in recent months, this type of cyber-attack doesn’t seem to slow down.

Organizations that have shown to be financially capable of paying ransom, including government agencies, as well as organizations in the healthcare and education sectors are particularly targeted by this attack.

You don’t have to be a victim of a ransomware attack. Stop cybercriminals before they get the leverage.

Speak with our cybersecurity experts today and stop worrying about ransomware.