Monti is a ransomware group that emerged in December 2022, operating with primarily financial motivations through targeted encryption attacks against organizations across multiple sectors. The group's origin and specific affiliations remain largely undocumented in public threat intelligence reports, though their operational patterns suggest they function as an independent ransomware operation rather than a established Ransomware-as-a-Service model. Monti's attack methodology and specific technical details regarding initial access vectors, encryption methods, and data exfiltration practices have not been extensively documented in publicly available threat intelligence from major security firms or government agencies. The group has reportedly compromised approximately 110 victims since their emergence, with their targeting primarily focused on organizations in the United States, Canada, Germany, France, and Italy, showing a particular preference for business services, healthcare, manufacturing, and technology sectors. Limited public documentation exists regarding specific notable campaigns or high-profile attacks attributed to Monti, reflecting the group's relatively recent emergence and lower profile compared to more established ransomware operations. As of current reporting, Monti appears to remain an active threat, though comprehensive intelligence on their current operational status is limited in publicly available sources from major cybersecurity organizations and law enforcement agencies. The group has been linked to 110 public disclosures across our corpus. First observed on a leak site on December 7, 2022; most recent post May 8, 2025. The operation is currently inactive.
Sector and geography
This disclosure adds to ransomware activity in the Not Found sector, which has 4,859 disclosures indexed across all operators we track. Geographically, FENSTERMAKER is reported in United States, a country with 7,392 ransomware disclosures in our corpus.
How we know this. Darkfield monitors public ransomware leak sites continuously, archiving every new disclosure and the data later released against the victim. Each entry on this page is sourced from the operator's own publication and cross-checked against complementary OSINT feeds (RansomLook, ransomware.live, RansomWatch). We do not collect or host stolen data — only the metadata, timestamps and screenshots needed to make the public disclosure searchable and accountable. Records here are corrected when the original post is edited, retracted, or merged with another disclosure.
