Pierluigi Paganini January 07, 2022

Researchers warn of a new ransomware family, called ‘Night Sky,’ that uses a double-extortion model in attacks again businesses.

Researchers from MalwareHunterteam first spotted a new ransomware family dubbed Night Sky that implements a double extortion model in attacks aimed at businesses. Once encrypted a file, the ransomware appends the ‘.nightsky‘ extension to encrypted file names.

The ransomware gang started its operations on December 27, 2021, and has already hacked the corporate networks of two organizations from Bangladesh and Japan respectively. The gang has also set up a leak site on the Tor network where it will publish files stolen to the victims that will not pay the ransom.

According to BleepingComputer, the group demanded one of its victims, the payment of an initial ransom of $800,000 to recover the encrypted data. The researchers noticed that the Night Sky ransomware doesn’t encrypt .dll or .exe files, it also doesn’t target the following list of files or folders:

AppData
Boot
Windows
Windows.old
Tor Browser
Internet Explorer
Google
Opera
Opera Software
Mozilla
Mozilla Firefox
$Recycle.Bin
ProgramData
All Users
autorun.inf
boot.ini
bootfont.bin
bootsect.bak
bootmgr
bootmgr.efi
bootmgfw.efi
desktop.ini
iconcache.db
ntldr
ntuser.dat
ntuser.dat.log
ntuser.ini
thumbs.db
Program Files
Program Files (x86)
#recycle

The ransomware drops a ransom note named NightSkyReadMe.hta in each folder, the file includes contact emails, and hardcoded credentials to the victim’s negotiation page along with the credentials to log in to the Rocket.Chat to contact the operators.

Experts pointed out that the gang communicates with victims via email and a clear website running an instance of the Rocket.Chat.

Researchers believe that in the next months other organizations will be targeted by the Night Sky ransomware group.

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Pierluigi Paganini

(SecurityAffairs – hacking, ransomware)

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