--- title: "John G. Yphantides law corporation network data incident" description: "John G. Yphantides law corporation disclosed file acquisition from its network during April 9–13, 2026." incident_type: "Data incident" status: "active" last_modified: "2026-10-17" canonical_url: "https://www.ally.security/incidents/john-g-yphantides-network-data-incident-2026" markdown_url: "https://www.ally.security/incidents/john-g-yphantides-network-data-incident-2026.md" stix_url: "https://www.ally.security/incidents/john-g-yphantides-network-data-incident-2026/stix.json" --- # John G. Yphantides law corporation network data incident An October 2026 notice describes an April network intrusion and file theft. Last modified Oct 17, 2026 · 1 source ## Summary - **Environment:** Law corporation network - **Operational impact:** Files acquired; service disruption not quantified - **Financial impact:** No financial loss quantified in the reviewed evidence ## What happened [John G. Yphantides, a Professional Law Corporation](https://oag.ca.gov/ecrime/databreach/reports/sb24-631484), reported that an unauthorized actor accessed its network and acquired files between April 9 and April 13, 2026. [1](#source-1) ## Impact The [notification letter](https://oag.ca.gov/system/files/John%20G.%20Yphantides%20-%20Notice%20of%20Data%20Event%20-%20CA_0.pdf) identifies names among the affected information; other individualized fields are blank in the public copy. It provides no affected-person count. [1](#source-1) ## Timeline ### April 9, 2026 — Access began Start of the reported interval. [1](#source-1) ### April 13, 2026 — Reported access ended End of the reported interval. [1](#source-1) ### September 14, 2026 — Personal information identified The file review identified information about notified individuals. [1](#source-1) ### October 16, 2026 — Notice issued The firm issued its [letter](https://oag.ca.gov/system/files/John%20G.%20Yphantides%20-%20Notice%20of%20Data%20Event%20-%20CA_0.pdf). [1](#source-1) ### October 17, 2026 — Briefing updated This briefing was last reviewed and updated on October 17, 2026. ## Threat Group & Attack Vector Initial access, malware and the discovery date are not established. September 14 is a file-review finding, not a confirmed detection date. ### Actors - No threat actor group has been identified in the reviewed public evidence. ### TTPs - No specific MITRE ATT\&CK technique is currently mapped for this case. ## Response The firm secured systems, engaged forensic specialists and reviewed safeguards. It offered twelve months of credit monitoring. [1](#source-1) ## Assets [Download the case-scoped STIX 2.1 bundle]() ## Sources Primary source records used to research this incident. ### John G. Yphantides, a Professional Law Corporation — Notice of Data Breach official · John G. Yphantides, a Professional Law Corporation · Oct 16, 2026
Evidence ledger Review the supporting structured claims. 1. **Resulted In · 100% confidence · current** John G. Yphantides law corporation network data breach: Unauthorized access began 2. **Began At · 100% confidence · current** John G. Yphantides law corporation network data breach: 2026-04-09 3. **Occurred At · 100% confidence · current** Reported access interval ended: 2026-04-13 4. **Resulted In · 100% confidence · current** John G. Yphantides law corporation network data breach: Reported access interval ended 5. **Resulted In · 100% confidence · current** Personal-information finding: The review identified information about notified individuals. 6. **Resulted In · 100% confidence · current** John G. Yphantides law corporation network data breach: Personal-information finding 7. **Occurred At · 100% confidence · current** Unauthorized access began: 2026-04-09 8. **Exposed Data Category · 100% confidence · current** Acquired law-corporation files: Names 9. **Resulted In · 100% confidence · current** John G. Yphantides law corporation network data breach: On September 14, 2026, the file review established that information about notified individuals was in the affected files. 10. **Resulted In · 100% confidence · current** Notification letter issued: The firm issued its notification letter. 11. **Occurred At · 100% confidence · current** Personal-information finding: 2026-09-14 12. **Resulted In · 100% confidence · current** John G. Yphantides law corporation network data breach: An unauthorized actor accessed the law corporation’s network and acquired files between April 9 and April 13, 2026. 13. **Resulted In · 100% confidence · current** John G. Yphantides law corporation network data breach: Acquired law-corporation files 14. **Affected Organization · 100% confidence · current** John G. Yphantides law corporation network data breach: John G. Yphantides, a Professional Law Corporation 15. **Resulted In · 100% confidence · current** John G. Yphantides law corporation network data breach: Notification letter issued 16. **Resulted In · 100% confidence · current** John G. Yphantides law corporation network data breach: The firm secured its systems, engaged forensic specialists, and was adding safeguards and reviewing privacy and security procedures. 17. **Ended At · 100% confidence · current** John G. Yphantides law corporation network data breach: 2026-04-13 18. **Occurred At · 100% confidence · current** Notification letter issued: 2026-10-16 19. **Resulted In · 100% confidence · current** John G. Yphantides law corporation network data breach: The notice offers twelve months of credit monitoring through Cyberscout. 20. **Disclosed At · 100% confidence · current** John G. Yphantides law corporation network data breach: 2026-10-16 21. **Resulted In · 100% confidence · current** Unauthorized access began: Start of the network-access and file-acquisition interval. 22. **Resulted In · 100% confidence · current** Reported access interval ended: End of the documented interval.