☠️ Gunra Ransomware: Encrypts Windows Files & Deletes Shadow Copies — New Threat Emerges

Published on: July 26, 2025

By: CyberDudeBivash Editorial Team

Website:cyberdudebivash.com

🚨 What’s Going On: New Gunra Ransomware Arrives

A new ransomware strain called Gunra has emerged in early 2025, exploiting Windows environments with lightning speed. Building on the legacy of Conti, the group uses double-extortion tactics—encrypting files, threatening to leak data, and urgently demanding ransom. More than a dozen high-profile organizations in sectors like healthcare, manufacturing, and logistics were impacted within Gunra’s first three months of operation.CYFIRMA+2Cyber Security News+2intertecsystems.com+2

🧩 How Gunra Works: Technical Breakdown

🔐 File Encryption Mechanism

• Gunra appends a .ENCRT extension to encrypted files.
• It deploys RSA‑2048 keys to encrypt a ChaCha20 session key, maximizing speed through multithreaded execution across logical CPU cores.intertecsystems.com+2Cyber Security News+2CYFIRMA+2
• The executable skips system files and executables to maintain OS stability and ensure ransom notes remain visible.intertecsystems.com+2Cyber Security News+2Securonix+2

🌫 Double-Extortion Strategy

• Attackers steal sensitive data before encryption.
• Threaten to publish stolen data online within five days, unless payment is made.
• They offer a limited decryption of files to prove legitimacy.intertecsystems.com+1CYFIRMA+1

💥 Shadow Copy Deletion

Gunra uses WMI commands to enumerate and delete Windows Volume Shadow Copies—specifically via:

cmd.exe /c C:\Windows\System32\wbem\WMIC.exe shadowcopy where "ID={GUID}" delete

This ensures recovery through built-in Windows mechanisms is disabled.Securonix+4Cyber Security News+4CYFIRMA+4

⏳ Anti-Forensic & Execution Tactics

• Detects debugging environments to evade analysis.
• Leverages ping in shell commands for execution delay and self-cleaning routines to minimize traceability.CYFIRMASecuronix

🧭 Who’s Being Targeted?

Gunra is targeting major enterprises and critical sectors via:

• Compromised RDP credentials
• Misconfigured VPN gateways
• Internal lateral movement tools like PsExec or Group Policy to deploy ransomware laterally.CYFIRMA+6Cyber Security News+6Securonix+6

Sector-wise, victims include healthcare, manufacturing, logistics, and technology firms—some already facing threats to expose medical records of millions.intertecsystems.comCyber Security News

🔒 Impact & Risks

🧰 Defense Guidance: How to Protect Against Gunra

✅ 1. Harden Remote Access

• Disable RDP where possible and enforce MFA.
• Restrict RDP to whitelist IPs via VPN or firewall rules.

✅ 2. Patch & Update Everything

• Keep Windows, VPN gateways, and remote access tools fully patched.
• Monitor dark web for exposed credentials.

✅ 3. Backup & Recovery Planning

• Use air-gapped or immutable backups.
• Regularly validate recovery from backups.

✅ 4. Utilize Anti-Ransomware Controls

• Deploy AppLocker or WDAC to block unexpected shells.
• Monitor and restrict execution from temp directories and user profiles.intertecsystems.com+1CYFIRMA+1Infosec InstituteSecuronix

✅ 5. WMI & Process Monitoring

• Flag suspicious WMI usage—especially calls to Win32_ShadowCopy.
• Monitor behavior like unintended ping sequences or rapid spawning processes.Infosec Institute+1Cyber Security News+1

✅ 6. File Integrity Monitoring

• Apply File Integrity Monitoring (FIM) to critical system and data files.
• Automatically alert on unexpected changes to file state or names.CYFIRMA

✅ 7. Employee Awareness

• Train employees to spot phishing and social engineering entry points.
• Conduct tabletop simulations of ransomware breach scenarios.CYFIRMA

🧠 Expert Commentary

“Gunra shows how legacy ransomware tactics (like shadow-copy deletion and domain pivoting) are being optimized for more speed and stealth. The sophistication of the double-extortion model in healthcare and logistics sectors raises the stakes.”
— CYFIRMA researchersInfosec Institute+5CYFIRMA+5Cyber Security News+5

🔮 Final Takeaway

Gunra isn't just another ransomware strain—it combines rapid encryption, double-extortion psychology, and anti-recovery tactics to pressure victims into paying. Organizations using vulnerable RDP or VPN access must act decisively to build robust detection, isolation, and backup systems.

💬 Join the Conversation

• Has your organization experienced a Gunra-style incident or exposure?
• What ransomware defense strategies have worked for you?

Share your insights in the comments or tweet us at @CyberDudeBivash.

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Tags: #GunraRansomware #WindowsSecurity #Ransomware #ShadowCopyDeletion #DoubleExtortion #CyberThreatIntel #Cybersecurity #CyberDudeBivash