Based on available public documentation, Keyholder is an obscure ransomware operation that was first observed in April 2015, with limited documented activity suggesting primarily financially motivated attacks. The group's origin and affiliations remain largely unknown due to minimal public reporting from major security firms and law enforcement agencies, with no clear indication of whether they operate as a Ransomware-as-a-Service model or as an independent entity. Available intelligence indicates extremely limited activity with only one publicly documented victim, suggesting either a highly targeted approach or a short-lived operation that failed to gain significant traction in the ransomware landscape. The group has demonstrated targeting of emergency services sectors within the United States, though the specific attack methodology, tools, and extortion tactics employed remain undocumented in public threat intelligence reporting. Given the sparse public documentation and lack of recent reporting from CISA, FBI, or major security research firms since the initial 2015 observation, the current operational status of Keyholder remains unclear, with the group likely having ceased operations or remaining dormant. The group has been linked to 1 public disclosures across our corpus. First observed on a leak site on April 4, 2015. The operation is currently inactive.
Sector and geography
This disclosure adds to ransomware activity in the Emergency Services sector, which has 9 disclosures indexed across all operators we track. Geographically, Tewksbury Police Department is reported in United States, a country with 11,033 ransomware disclosures in our corpus.
If your organisation is affected
A listing by keyholder means Tewksbury Police Department appeared on a ransomware extortion site and data attributed to it has been published. If this is your organisation, or a supplier you depend on, the priority is to confirm the intrusion and contain it before the window to act closes.
- Engage your incident-response team and preserve forensic evidence before remediating — do not wipe affected systems first.
- Force a password reset and revoke active sessions for exposed accounts; rotate any credentials, API keys or certificates that may have been in the stolen data.
- Assess regulatory notification duties (GDPR, NIS2, sector regulators) — many carry a 72-hour reporting clock from awareness.
- Report the incident to your national CERT, CISA (United States), as required for your jurisdiction.
- Monitor for the data appearing on keyholder's leak site and across paste and breach channels, and brief downstream partners who may be exposed through you.
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.
