J
Since May 2, 2025, J has listed 41 organizations on its leak site.
Listings per month
- Total listings
- 41
- First listing
- May 2, 2025
- Latest listing
- Nov 9, 2025
- MITRE ATT&CK techniques
- 0
J is an emerging ransomware group that launched its leak site in May 2025, claiming over 41 victims by late 2025 including FAI Aviation Group (Germany), operating primarily as a leak-site-centric extortion identity with limited public technical analysis.
It posted no listings in the last 12 months.
Most targeted country: United States, with 6 listings (15% of the total).
Most targeted sector: Technology, with 8 listings (20% of the total).
Targeted countries
Showing 10 of 41 results
What does a ransomware group do?
Ransomware groups break into corporate networks, move data out and encrypt systems. If the ransom is not paid, they list the organization on a leak site and threaten to publish the data.
What should you do if your organization is listed on a leak site?
- Record the listing and any published sample files; do not visit the leak site from the corporate network.
- Isolate affected systems and preserve logs without deleting them.
- Determine which data left the organization; if personal data is involved, review notification obligations with your legal team.
- Make any decision about the ransom demand together with legal, management and incident response.
- Do not bring systems back online before the attacker’s entry point is closed.
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Customer intelligence on top of Infostealer Detection: leaked accounts of end users who sign in to your site.