Registration is now open for SASE Week 2023! Get on the guest list.

  • Security Service Edge Products

    Protect against advanced and cloud-enabled threats and safeguard data across all vectors.

  • Borderless SD-WAN

    Confidently provide secure, high-performance access to every remote user, device, site, and cloud.

The platform of the future is Netskope

Intelligent Security Service Edge (SSE), Cloud Access Security Broker (CASB), Cloud Firewall, Next Generation Secure Web Gateway (SWG), and Private Access for ZTNA built natively into a single solution to help every business on its journey to Secure Access Service Edge (SASE) architecture.

Go to Products Overview
Netskope video
Borderless SD-WAN: Ushering in the New Era of Borderless Enterprise

Netskope Borderless SD-WAN offers an architecture that converges zero trust principles and assured application performance to provide unprecedented secure, high-performance connectivity for every site, cloud, remote user, and IoT device.

Read the article
Borderless SD-WAN
  • NewEdge

    NewEdge is the world’s largest, highest-performing security private cloud.

  • Cloud Security Platform

    Unrivaled visibility and real-time data and threat protection on the world's largest security private cloud.

  • Technology Partners & Integrations

    Netskope partners with the strongest companies in enterprise technology.

Embrace a Secure Access Service Edge (SASE) architecture

Netskope NewEdge is the world’s largest, highest-performing security private cloud and provides customers with unparalleled service coverage, performance and resilience.

Learn about NewEdge
NewEdge
Your Network of Tomorrow

Plan your path toward a faster, more secure, and more resilient network designed for the applications and users that you support.

Get the white paper
Your Network of Tomorrow
Netskope Cloud Exchange

The Netskope Cloud Exchange (CE) provides customers with powerful integration tools to leverage investments across their security posture.

Learn about Cloud Exchange
Netskope video
Make the move to market-leading cloud security services with minimal latency and high reliability.

Learn about NewEdge
Lighted highway through mountainside switchbacks
Safely enable the use of generative AI applications with application access control, real-time user coaching, and best-in-class data protection.

Learn how we secure generative AI use
Safely Enable ChatGPT and Generative AI
Zero trust solutions for SSE and SASE deployments

Learn about Zero Trust
Boat driving through open sea
Netskope enables a safe, cloud-smart, and fast journey to adopt cloud services, apps, and public cloud infrastructure.

Learn about Industry Solutions
Wind turbines along cliffside
  • Resources

    Learn more about how Netskope can help you secure your journey to the cloud.

  • Blog

    Learn how Netskope enables security and networking transformation through security service edge (SSE).

  • Events & Workshops

    Stay ahead of the latest security trends and connect with your peers.

  • Security Defined

    Everything you need to know in our cybersecurity encyclopedia.

Security Visionaries Podcast

Leveling Up the SASE Conversation
Robert Arandjelovic and Gerry Plaza sit down to chat with Max Havey about how embracing a SASE journey can help bring networking and security teams closer together.

Play the podcast
Leveling Up the SASE Conversation
Latest Blogs

How Netskope can enable the Zero Trust and SASE journey through security service edge (SSE) capabilities.

Read the blog
Sunrise and cloudy sky
SASE Week 2023: Your SASE journey starts now!

Join us for the fourth annual SASE Week, September 26-28.

Get on the guest list
SASE Week 2023
What is Security Service Edge?

Explore the security side of SASE, the future of network and protection in the cloud.

Learn about Security Service Edge
Four-way roundabout
  • Our Customers

    Netskope serves more than 2,000 customers worldwide including more than 25 of the Fortune 100

  • Customer Solutions

    We are here for you and with you every step of the way, ensuring your success with Netskope.

  • Netskope Community

    Learn from other network, data, and security professionals.

  • Training and Certification

    Netskope training will help you become a cloud security expert.

We help our customers to be Ready for Anything

See our Customers
Woman smiling with glasses looking out window
Netskope’s talented and experienced Professional Services team provides a prescriptive approach to your successful implementation.

Learn about Professional Services
Netskope Professional Services
The Netskope Community can help you and your team get more value out of products and practices.

Go to the Netskope Community
The Netskope Community
Secure your digital transformation journey and make the most of your cloud, web, and private applications with Netskope training.

Learn about Training and Certifications
Group of young professionals working
  • Company

    We help you stay ahead of cloud, data, and network security challenges.

  • Why Netskope

    Cloud transformation and work from anywhere have changed how security needs to work.

  • Leadership

    Our leadership team is fiercely committed to doing everything it takes to make our customers successful.

  • Partners

    We partner with security leaders to help you secure your journey to the cloud.

Supporting sustainability through data security

Netskope is proud to participate in Vision 2045: an initiative aimed to raise awareness on private industry’s role in sustainability.

Find out more
Supporting Sustainability Through Data Security
Highest in Execution. Furthest in Vision.

Netskope recognized as a Leader in the 2023 Gartner® Magic Quadrant™ for Security Service Edge.

Get the report
Netskope recognized as a Leader in the 2023 Gartner® Magic Quadrant™ for Security Service Edge.
Thinkers, builders, dreamers, innovators. Together, we deliver cutting-edge cloud security solutions to help our customers protect their data and people.

Meet our team
Group of hikers scaling a snowy mountain
Netskope’s partner-centric go-to-market strategy enables our partners to maximize their growth and profitability while transforming enterprise security.

Learn about Netskope Partners
Group of diverse young professionals smiling

Netskope Threat Coverage: Night Sky

Jan 11 2022

Summary

Naming themselves Night Sky, a new ransomware family was spotted on the first day of 2022, by the MalwareHunterTeam. They appear to work in the RaaS (Ransomware-as-a-Service) model, similar to other ransomware groups like REvil, LockBit, and Hive, publishing stolen data exfiltrated throughout the attack in a deep web site if the ransom is not paid by the victim.

Example of Night Sky ransomware message in their deep web site.
Night Sky ransomware message in their deep web site.

Currently, there are two companies listed on their deep web site, where the group has published the victim’s allegedly stolen data.

Screenshot of the two victim’s listed on the Night Sky website.
Two victim’s listed on the Night Sky website.

Night Sky publishes a list of everything they claim to have stolen.

Screenshot of list of allegedly stolen data by Night Sky group.
List of allegedly stolen data by Night Sky group.

Aside from this list, there are also screenshots of the stolen files and data. The group demands the victim to contact them within a week after the attack, claiming that the contact website will be disabled after this period, eliminating the chances of recovery through payment.

Screenshot of Night Sky’s details on their website.
Night Sky’s details on their website.

Researchers have found that the Night Sky ransomware group was using the Log4Shell vulnerability (CVE-2021-44228) to successfully infect their targets as early as January 4, 2022. It’s not the first time a ransomware family has been found utilizing this vulnerability either, as Khonsari was using it in December 2021.

Furthermore, similarities between Night Sky and Rook ransomware were found by comparing their binaries, containing only a few differences in the encryption algorithm. However, at this point it’s unclear if this is the same threat group or a code reuse.

Threat

Only two samples of Night Sky were found in the wild so far, being both 64-bit executables using VMProtect software, which adds a strong protection against analysis and reverse engineering.

Example of Night Sky using VMProtect.
Night Sky using VMProtect.

Before encrypting the files, Night Sky uses a hardcoded mutex to verify if another instance of the ransomware is already running.

Example of Night Sky checking / creating the mutex.
Night Sky checking / creating the mutex.

We created a small code that creates the same mutex and we confirmed that the ransomware skips the encryption if the object already exists. 

Once running, Night Sky starts listing all directories, skipping the following folders and files:

  • #recycle
  • $Recycle.Bin
  • All Users
  • AppData
  • autorun.inf
  • Boot
  • boot.ini
  • bootfont.bin
  • bootmgfw.efi
  • bootmgr
  • bootmgr.efi
  • bootsect.bak
  • desktop.ini
  • Google
  • iconcache.db
  • Internet Explorer
  • Mozilla
  • Mozilla Firefox
  • ntldr
  • ntuser.dat
  • ntuser.dat.log
  • ntuser.ini
  • Opera
  • Opera Software
  • Program Files
  • Program Files (x86)
  • ProgramData
  • thumbs.db
  • Tor Browser
  • Windows
  • Windows.old
Screenshot of list of folders and files Night Sky skips the encryption
List of folders and files Night Sky skips the encryption.

NightSky also skips files with the extensions “.exe”, “.dll”, and “.nightsky”.

Screenshot of Night Sky won’t encrypt files with these extensions.
Night Sky won’t encrypt files with these extensions.

If the file doesn’t match the criteria above, Night Sky adds the “.nightsky” extension and starts the encryption routine.

Example of ransomware adding the “.nightsky” extension to encrypted files.
Ransomware adding the “.nightsky” extension to encrypted files.

Night Sky uses the Mbed TLS library functions during the encryption.

Screenshot of Mbed TLS library found in Night Sky Ransomware.
Mbed TLS library found in Night Sky Ransomware.

Throughout the encryption process, Night Sky uses a combination of AES-128-CBC for file encryption, and a combination of RSA to encrypt the keys, which is appended to the file. This page contains more detailed information about Night Sky encryption processes, as well as similarities between Rook ransomware.

Example of Night Sky attacker’s public RSA (2048 bit) key used in the encryption process
Night Sky attacker’s public RSA (2048 bit) key used in the encryption process

The ransomware creates the ransom note in HTA format in every single directory, named “NightSkyReadMe.hta”.

Screenshot of Night Sky encrypted files along with the ransom note.
Night Sky encrypted files along with the ransom note.

The ransom note contains some of the information that is also published on the deep web site, along with the URL and contact information.

Example of Night Sky ransom note.
Night Sky ransom note.

Protection

Netskope Threat Labs is actively monitoring this campaign and has ensured coverage for all known threat indicators and payloads. 

  • Netskope Threat Protection
    • Win64.Ransomware.NightSky
  • Netskope Advanced Threat Protection provides proactive coverage against this threat.
    • Gen.Malware.Detect.By.StHeur indicates a sample that was detected using static analysis
    • Gen.Malware.Detect.By.Sandbox indicates a sample that was detected by our cloud sandbox

IOCs

A full list of IOCs and a Yara rule are all available in our Git repo.

author image
Gustavo Palazolo
Gustavo Palazolo is an expert in malware analysis, reverse engineering and security research, working many years in projects related to electronic fraud protection. He is currently working on the Netskope Research Team, discovering and analyzing new malware threats.

Stay informed!

Subscribe for the latest from the Netskope Blog