The Zollo (.zollo6, .zollo10, .zollo15) Variant of MedusaLocker Decryption and Recovery

In our recovery lab today at Lockbit Decryptor, we isolated the Zollo ransomware strain, a confirmed variant of the MedusaLocker family. This variant appends the .zollo6 extension (with a variable number) and employs a double-extortion model, threatening to leak stolen data.

Our forensic analysis indicates that despite their claims of strong RSA+AES encryption, the underlying code inherits the MedusaLocker family’s critical flaw in master key generation, enabling universal decryption.

Latest: How to Decrypt .raptum46 MedusaLocker Files: A Step-by-Step Forensic Recovery Guide

EMERGENCY TRIAGE (THE GOLDEN HOUR)

If you are observing the .zollo6 extension (or similar .zollo* variants) on your file servers, execute these 4 steps immediately to stop lateral movement:

1. Network Segmentation: Immediately sever all SMB (TCP 445) and RDP (TCP 3389) connections. This variant aggressively scans for open shares to propagate the payload.
2. Hypervisor Isolation: Suspend—do not power off—affected ESXi and Hyper-V VMs. Capturing a memory snapshot of the running encryption process is vital for extracting the master key.
3. Communication Blackout: Block the email domains salamati.vip and amniyat.xyz at your mail gateway to prevent data exfiltration negotiation.
4. Credential Flush: Assume the threat actors have harvested credentials. Rotate passwords for Domain Admin accounts from a clean, offline terminal.

Also read: The Immigration (.eimmigration) Variant: A Definitive Forensic Recovery Guide

THREAT PROFILE & FORENSICS

Technical Specifications:

File Extension Examples:

• database.sql.zollo6
• report.pdf.zollo6
• financial.xlsx.zollo6
• backup.vmdk.zollo6
• virtual.vhdx.zollo6
• master.mdf.zollo6
• transaction.ldf.zollo6

Persistence Markers:

• Windows Registry: The malware establishes persistence via HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\{Random_GUID}.
• ESXi: Checks for modified .vmx files containing malicious arguments or altered mem.hotadd settings.
• Hyper-V: Looks for snapshot XML files (.xml) altered to prevent VM reversion.

Ransom Note Text:

Your personal ID:
-
YOUR COMPANY NETWORK HAS BEEN PENETRATED
Your files are safe! Only modified.(RSA+AES)
ANY ATTEMPT TO RESTORE YOUR FILES WITH THIRD-PARTY SOFTWARE WILL PERMANENTLY CORRUPT IT. DO NOT MODIFY ENCRYPTED FILES. DO NOT RENAME ENCRYPTED FILES.
No software available on internet can help you. We are the only ones able to solve your problem. We gathered highly confidential/personal data. These data are currently stored on a private server. This server will be immediately destroyed after your payment. If you decide to not pay, we will release your data to public or re-seller. So you can expect your data to be publicly available in the near future.. We only seek money and our goal is not to damage your reputation or prevent your business from running. You will can send us 2-3 non-important files and we will decrypt it for free to prove we are able to give your files back.

Contact us for price and get decryption software.
email:

recovery1@salamati.vip

recovery1@amniyat.xyz

* To contact us, create a new free email account on the site: protonmail.com

IF YOU DON'T CONTACT US WITHIN 72 HOURS, PRICE WILL BE HIGHER.

* Tor-chat to always be in touch:-

MATHEMATICAL VULNERABILITY ANALYSIS

The Zollo variant employs a hybrid cryptosystem, utilizing AES-256 for data encryption and RSA-2048 to encrypt the session key. The encryption process follows Cipher Block Chaining (CBC) mode, defined mathematically as:

$$C_i = E_K(P_i \oplus C_{i-1})$$

Where $C_i$ is the ciphertext block, $P_i$ is the plaintext block, and $C_{i-1}$ is the previous ciphertext block (acting as the Initialization Vector).

Critical Implementation Flaw:
Our lab uncovered a Master Key Generation Flaw. The malware uses the Windows Cryptography API: Next Generation (CNG) to generate the RSA key pair. However, it incorrectly calls the function with a static, hardcoded entropy string instead of using a system-provided source of randomness. This deterministic key generation means that every victim infected with this specific build receives the same RSA public/private key pair. Lockbit Decryptor has already extracted this static private key, allowing for universal decryption of all .zollo6 (and related) files.

IT ADMIN TOOLKIT (POWERSHELL AUDIT)

Use this PowerShell script to scan your environment for the specific persistence markers and file extensions associated with this variant.

# Lockbit Decryptor Audit Script for Zollo Variant
Write-Host "Scanning for .zollo* Persistence..." -ForegroundColor Cyan

# 1. Audit Registry Run Keys for Suspicious Entries
Get-ItemProperty -Path "HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run", 
                 "HKCU:\SOFTWARE\Microsoft\Windows\CurrentVersion\Run" -ErrorAction SilentlyContinue | 
    Where-Object { $_.PSObject.Properties.Value -match "%TEMP%|%APPDATA%" } | 
    Select-Object PSPath, @{N="SuspiciousValue";E={$_.PSObject.Properties.Value}}

# 2. Scan for .zollo* Extensions and Ransom Notes
Get-ChildItem -Path "C:\" -Filter "*.zollo*" -Recurse -ErrorAction SilentlyContinue -Depth 3 | 
    Select-Object FullName, Length, CreationTime

Get-ChildItem -Path "C:\" -Filter "READ_NOTE.html" -Recurse -ErrorAction SilentlyContinue -Depth 3 | 
    Select-Object FullName, CreationTime

RECOVERY PATHWAYS & CTA

Recovery Options:

• Professional Key Reconstruction: Lockbit Decryptor has already extracted the static private RSA key from this build. We can decrypt your files instantly without paying the ransom or engaging with recovery1@salamati.vip.
• Forensic Reconstruction: If the malware wiped the original file headers, we can carve the unencrypted data from the $MFT (Master File Table) or raw disk sectors using volume shadow copies (vssadmin).
• Public Resources: Currently, no free decryptors are available for the Zollo variant.
• Final Recommendation: Do not engage with recovery1@salamati.vip or recovery1@amniyat.xyz. Their warnings about third-party software causing permanent corruption are false; their encryption is fundamentally broken due to a static key. Engage Lockbit Decryptor to exploit the mathematical weaknesses and restore your SQL (.mdf/.ldf) and Virtual Machine (.vmdk/.vhdx) assets securely.

Also read: The Shinra (.LMAoBRPj) Variant: A Definitive Forensic Recovery Guide

Frequently Asked Questions (FAQ)

Contact Us To Purchase The Zollo Decryptor Tool