---
schema_version: "secwatch.filing_event.v1"
accession: "0001537435-23-000036"
form_type: "8-K"
ticker: "TGEN"
cik: "0001537435"
company_name: "TECOGEN INC."
filed_at: "2023-05-03T23:59:59+00:00"
generated_at: "2026-06-16T01:03:04.769416+00:00"
event_type: "cyber"
sentiment: "negative"
materiality_score: 0.65
calibrated_materiality_score: 0.65
confidence: "high"
source: SEC EDGAR
---

# Tecogen discloses ransomware attack on April 28; network restored by May 1

## Summary
- Attack was a spear phishing attempt via the company's VPN; traces found on two workstations.
- Hard disks of affected workstations permanently removed; files restored from prior evening's backup.
- Network fully operational by May 1, 2023; all passwords changed and user accounts audited.
- VPN access disabled pending implementation of multi-factor authentication for network and workstations.
- Company reviewing improved cyber threat protection software and hardware solutions.

## SEC filing metadata
- accession: 0001537435-23-000036
- form_type: 8-K
- ticker: TGEN
- cik: 0001537435
- company_name: TECOGEN INC.
- filed_at: 2023-05-03T23:59:59+00:00
- event_type: cyber
- sentiment: negative
- materiality_score: 0.65
- calibrated_materiality_score: 0.65
- confidence: high
- sec_items: 8.01
- EDGAR index: https://www.sec.gov/Archives/edgar/data/1537435/000153743523000036/0001537435-23-000036-index.htm
- EDGAR primary document: https://www.sec.gov/Archives/edgar/data/1537435/000153743523000036/tgen-20230503.htm

## Machine-readable alternates
- HTML: https://secwatch.observer/filing/0001537435-23-000036
- JSON: https://secwatch.observer/filing/0001537435-23-000036.json
- Plain text: https://secwatch.observer/filing/0001537435-23-000036.txt

This AI-assisted summary is a reading aid. Review the linked SEC EDGAR filing before relying on any specific claim.