Pierluigi Paganini July 08, 2022

Taiwanese vendor QNAP wars of a new strain of ransomware, dubbed Checkmate, that is targeting its NAS devices.

The Taiwanese vendor QNAP is warning of a new family of ransomware targeting its NAS devices using weak passwords. Threat actors are targeting devices exposed online with the SMB service enabled, they perform brute-force attacks against accounts using weak passwords.

“A new ransomware known as Checkmate has recently been brought to our attention. Preliminary investigation indicates that Checkmate attacks via SMB services exposed to the internet, and employs a dictionary attack to break accounts with weak passwords.” reads the advisory published by the vendor. “Once the attacker successfully logs in to a device, they encrypt data in shared folders and leave a ransom note with the file name “!CHECKMATE_DECRYPTION_README” in each folder.”

The ransomware appends the .checkmate extension to the filenames of encrypted files, it drops a ransom note named !CHECKMATE_DECRYPTION_README on the infected devices.

BleepingComputer reported that several users on its forum claimed to have been infected with the Checkmate ransomware in June. According to the ransom note, the victims have to pay a $15,000 ransom in bitcoin to receive the decryptor. 

Below is the content of the ransom not shared by a victim on the BleepingComputer forum:

Here is the content: 

The vendor recommends not exposing the SMB service to the internet and using VPN to access the NAS and reduce the attack surface.

QNAP also recommends disabling SMB 1 and updating the operating system to the latest version.

The advisory also suggests reviewing all NAS accounts immediately to ensure they are using strong passwords and of course back up data and take snapshots regularly.

Below are step-by-step instructions to disable SMB 1 and update QTS, QuTS hero, or QuTScloud:

Disabling SMB 1

1. Log on to QTS, QuTS hero, or QuTScloud.
2. Go to Control Panel > Network & File > Win/Mac/NFS/WebDAV > Microsoft Networking.
3. Click Advanced Options.
   The Advanced Options window opens.
4. Next to Lowest SMB version, select SMB 2 or higher.
5. Click Apply.

Updating QTS, QuTS hero, or QuTScloud

1. Log on to QTS, QuTS hero or QuTScloud as administrator.
2. Go to Control Panel > System > Firmware Update.
3. Under Live Update, click Check for Update.
   QTS, QuTS hero or QuTScloud downloads and installs the latest available update.

In June, Bleeping Computer and MalwareHunterTeam researchers, citing user reports and sample submissions on the ID Ransomware platform, warned of a new wave of ech0raix ransomware attacks targeting QNAP Network Attached Storage (NAS) devices.

Follow me on Twitter: @securityaffairs and Facebook

Pierluigi Paganini

(SecurityAffairs – hacking, Checkmate ransomware)

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