Quantum is a ransomware group that emerged in September 2021, operating with primarily financial motivations and demonstrating a focus on high-value targets across English-speaking nations. The group's geographic targeting patterns and operational characteristics suggest possible connections to established ransomware ecosystems, though specific attribution or confirmed affiliations with other threat actors remain undocumented in public reporting. Quantum operators typically employ double extortion tactics, combining data encryption with the threat of public data exposure to maximize pressure on victims, and their campaigns have consistently targeted sectors with critical operational dependencies including business services, manufacturing, and information technology infrastructure. The group has maintained a relatively low public profile compared to other major ransomware operations, with their 68 documented victims representing a more selective approach to target acquisition rather than broad-scale campaigns. Despite limited public law enforcement reporting specifically focused on Quantum operations, the group's continued activity pattern suggests they remain an active threat as of recent observations, though comprehensive operational details remain scarce in publicly available threat intelligence reporting. The group has been linked to 68 public disclosures across our corpus. First observed on a leak site on September 9, 2021; most recent post December 9, 2022. The operation is currently inactive.
Also tracked as: QuantumLocker, Mount Locker, DagonLocker.
Sector and geography
Geographically, MCV Holding Company LLC 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.
