Cicada3301 is a recently emerged ransomware group that began operations in June 2024, primarily motivated by financial gain through extortion activities targeting organizations across multiple sectors. The group's origin and affiliations remain largely undocumented in public threat intelligence reporting, with limited information available regarding their operational structure or potential connections to other cybercriminal organizations. Based on observed targeting patterns, Cicada3301 has demonstrated a preference for attacking business services, technology, manufacturing, and financial sector organizations, with their operations concentrated primarily in English-speaking countries including the United States, United Kingdom, and Canada, as well as extending to Spain and Singapore. The group has successfully compromised approximately 75 known victims since their emergence, though specific details regarding their attack methodologies, initial access vectors, encryption techniques, and extortion tactics have not been extensively documented in publicly available threat intelligence reports from major cybersecurity firms or government agencies. Given the limited public documentation available from CISA, FBI, Mandiant, or other reputable security researchers, the group's current operational status, technical capabilities, and specific attack infrastructure remain largely uncharacterized in open-source intelligence reporting. As of the most recent observations, Cicada3301 appears to remain active in conducting ransomware operations, though comprehensive analysis of their tactics, techniques, and procedures awaits more detailed public reporting from established threat intelligence sources. The group has been linked to 75 public disclosures across our corpus. First observed on a leak site on June 20, 2024; most recent post September 4, 2025. The operation is currently inactive.
Sector and geography
This disclosure adds to ransomware activity in the Education sector, which has 1,082 disclosures indexed across all operators we track. Geographically, Substitute Teacher Service is reported in United States, a country with 11,033 ransomware disclosures in our corpus.
If your organisation is affected
A listing by Cicada3301 means Substitute Teacher Service 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 Cicada3301'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.
