Yason Ransomware ([Yason@mailum.com]) – File Recovery & Threat Analysis (2026 Update)

Direct Answer: The emerging Yason ransomware variant—identifiable by the [Yason@mailum.com] file marker, randomized alphanumeric extensions, and the Restore.txt ransom note—is a highly active extortion threat currently under urgent investigation. Because this is a newly observed strain as of September 2026, a public free decryptor does not exist, but early-stage diagnostic and recovery pathways are actively being established through our secure assessment lab.

From the front lines of incident response, encountering a zero-day or unidentified ransomware strain induces maximum panic. Let’s cut through the noise. My team is currently tracking the deployment of this specific locker. Unlike well-documented variants, the Yason actors utilize a randomized appended extension (e.g., .1tgYCO1d) tethered to their contact email. This indicates a likely dynamic or bespoke encryption mechanism. We are currently accepting encrypted samples through our secure intake portal to determine if the threat actors implemented full cryptographic locking or if they relied on vulnerable partial-encryption flaws that can be structurally bypassed.

Technical Identifiers for the Yason Ransomware Campaign

Identifier	Detail
Appended Pattern	.[Yason@mailum.com].[Random_8_Char_ID] (e.g., .1tgYCO1d)
Ransom Note Filename	Restore.txt
Primary Contact	Yason@mailum.com
Secondary Contact	Yason@cyberfear.com
Telegram Handle	@yasonIDs
Encryption Type	Active Analysis (Suspected dynamic/bespoke generation)

What Does the Attacker Want? The Full Ransom Note Text

Transparency is critical when dealing with a new threat actor. The Yason group keeps their initial demands brief, utilizing alternative communication channels like Telegram and secure email providers (cyberfear.com) to mask their location. Below is the complete, verbatim ransom note dropped by this strain.

Plaintext

If you want your files back, contact us at the email addresses shown below:

Yason@mailum.com

Yason@cyberfear.com

Telegram:  @yasonIDs

personal ID: 

# In subject line please write your personal ID

Check Your Spam Folder: After sending your emails, please check your spam/junk folder regularly to ensure you do not miss our response.

No Response After 24 Hours: If you do not receive a reply from us within 24 hours,
please create a new, valid email address (e.g., from Gmail, Outlook, etc.), and send your message again using the new email address.

The emphasis on spam folders and secondary email addresses indicates the attackers are actively combatting automated spam filters blocking their extortion domains—a common issue for newly established ransomware operators.

Also read: How to Decrypt Proton/Shinra v3.qPUvslnc Files Complete Guide

Immediate Actions: Preserving Unidentified Malware

When dealing with an uncategorized strain, your immediate actions dictate the likelihood of future recovery.

1. Sever Network Connections: Isolate the infected machine or server instantly. Unplug the Ethernet cable and disable Wi-Fi to halt any ongoing lateral movement or data exfiltration.
2. Properly Archive Samples for Analysis: Security researchers and our lab require both the Restore.txt file and a few encrypted files (ideally under 10MB) to analyze the damage. Crucial Note: When submitting samples, you must archive them into a standard .zip or .rar file. Do not attempt to rename the encrypted files or strip the [Yason@mailum.com] extension, as this destroys vital cryptographic headers needed for analysis.
3. Halt Antivirus Scans: Do not run automated removal tools yet. Aggressive AV software often quarantines or deletes the malicious executable payload before it can be forensically captured. We need that executable to reverse-engineer the encryption keys.

Our Professional Recovery & Analysis Process

Because this variant is in the active discovery phase, standard brute-force tools will fail. Our incident response framework is geared toward rapid reverse-engineering of emerging threats.

1. Secure Case Intake: Submit your Restore.txt and a properly zipped encrypted sample through our protected portal.
2. Cryptographic Profiling: Our researchers analyze the encrypted headers to determine the underlying algorithm (e.g., ChaCha20, RSA, AES) and map the file structure to check for partial-encryption shortcuts.
3. Threat Intelligence Matching: We cross-reference the Yason binary signatures against known ransomware families to see if this is simply a rebranded version of an older, breakable strain (such as a mutated STOP/Djvu or Phobos variant).
4. Proof-of-Life & Strategy: If a vulnerability is found in the malware’s execution, we mathematically derive the keys, perform a test decryption on your sample, and outline a full recovery operation.

Where to Go From Here

Do not panic and immediately message the Telegram handle. Engaging with operators of new ransomware campaigns signals desperation and often results in highly inflated, unpredictable ransom demands. Report the incident to IC3.gov and maintain offline backups of your encrypted state while our lab processes the initial samples.

About the Author:

This threat intelligence advisory was produced by the security team at StopDjvuDecryptor.org. As a specialized ransomware research laboratory and division of Cloud Cover LLC—an Ohio-based Managed Service Provider—we deliver enterprise-grade incident response. Led by Lead Researcher Brent Kenreich, our mission is to provide victims with mathematically verified recovery alternatives to paying cybercriminals.

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