HackingHospitalityHospitalityStolen CredentialsData ExfiltratedCustomer Data InvolvedIdentity (basic)Government IDCriticalContained

MGM RESORTS INTERNATIONAL

bd_05c59c84e811817f · schema v1 · pii pii-v1

Severity

Critical

Discovered

Sep 29, 2023

Filed

Oct 5, 2023

To disclose

6 days

Affected

1,857,761state residents only

Linked

14 filings

Confidence

67%

Full breach record for MGM RESORTS INTERNATIONAL →4 incidents on file

MGM Resorts International filed a supplemental notice with the Washington AG regarding a cybersecurity incident. Unauthorized access occurred on September 11, 2023, discovered on September 29, 2023. The incident affected 1,857,761 Washington residents, exposing names, contact info, DOB, driver's licenses, and SSNs/passports. MGM engaged forensic experts, coordinated with law enforcement, and provided credit monitoring.

J jump to incidentP pin to compareR raw source

Washington clock✓ WA AG ≤30d6 days discovery → filing

Incident timeline

undetected · 18 days

discovery → filing · 6 days

Sep 11, 2023

Begins

Sep 29, 2023

Discovered

Oct 5, 2023

Filed

This filing is one of 14 about the same incident.View merged incident

Linked disclosures

Why this link?

Regulatory filings (10) · sorted by filing gap

Oregon State AGbd_25f570b90148b65e2023-10-05Verified by operator
Vermont State AGbd_2cf9544a4111fecb2023-10-05Verified
Massachusetts State AGbd_3d31054a0da622772023-10-05Verified by operator
Indiana State AGbd_4bd1f6acdf646a9e2023-10-05Verified

Show 6 more filings ↓up to 61d gap

Maine State AGbd_4e28f4a3e508d5422023-10-05Verified
Delaware State AGbd_65dbfae801fc66ab2023-10-05Verified by operator
SEC 8-Kbd_6bbbeaea01c0cd312023-10-05Verified
Montana State AGbd_ee40948044b421ad2023-10-05Verified
South Carolina State AGbd_a165e7cc6b9dc2252023-10-06 · +1dVerified
California State AGbd_0171facdc96060a92023-12-05 · +61dVerified

Showing first 10 of 13 linked disclosures.

Name: MGM RESORTS INTERNATIONAL
norm: mgm resorts
Domain: mgmresorts.com

Name: MGM RESORTS INTERNATIONAL
norm: mgm resorts
Domain: mgmresorts.com
Industry: Hospitalityllm

Discovered: Sep 29, 2023
Breach occurred: Sep 11, 2023
Undetected for: 18 daysoccurrence → discovery
Materiality determined: —
Notification sent: Oct 5, 2023
Affected individuals: 1,857,761state-resident count only
Data types: Identity (basic)Government ID
Data elements: NameSocial Security numberDriver's licence numberDate of birthPassport number
WA-stated cause: Cyberattack
WA-stated duration: lifecycle 1-99dexposure 1-99d
WA-stated discovery: Found while ongoing
Attack vector: Unauthorized Access
MITRE ATT&CK: T1078 Valid AccountsT1119 Automated Collection
Threat actor: ExternalFinancial
Regulator citations: Notified Washington Office of the Attorney General
Initial access: valid_credentials

During the incident: Shutting down certain systems
Launched an investigation with the assistance of leading cybersecurity experts
Coordinating with law enforcement
Put in place additional safeguards to further protect its systems
Notifying relevant customers by email
Arranged to provide those customers with credit monitoring and identity protection services at no cost to them
Changes made: Put in place additional safeguards to further protect its systems
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 6 days(6 days from discovery to filing)
Compliance flags: WA AG ≤30d
Discovery-date grounding: letter-groundedThe discovery date is the detection date narrated in the notification letter — the defensible tier.

Status: No extraction artifact recorded for this disclosure.

Filing propagation · 11 filings · 10 states

View merged incident ↗

Oregon State AGOct 5 · first

Vermont State AGOct 5 · first

Massachusetts State AGOct 5 · first

Indiana State AGOct 5 · first

Maine State AGOct 5 · first

Delaware State AGOct 5 · first

SEC 8-KOct 5 · first

Montana State AGOct 5 · first

Washington State AGOct 5 · first · this page

South Carolina State AG+1d

California State AG+61d

Pattern: first filing Oct 5 (OR), last Dec 5 (CA) — a 61-day rolling notification. Rolling spreads often mean counsel is filing as thresholds trip per state. Why this link?

Cascade drawn from the first 10 linked disclosures of 13 — the full spread may be wider.

Evidence ladder

Leak-site claim

Attacker assertion only. Establishes: claim date, group, alleged victim.

Press / market report

Unlocks: incident narrative, operational impact. Still no compliance clock.

State AG / regulator filingThis record

Unlocks: discovery date, data types, affected count, compliance clock.

SEC 8-K / victim statement

Unlocks: materiality, stated response, full audit trail. Ceiling removed.

Source URL: https://agportal-s3bucket.s3.amazonaws.com/databreach/BreachA26707.pdf
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Oct 5, 2023
Raw hash: 8aed8dbdb8611b63230895b0b62f41e2227d5763c232af278ba2ed7305fd4da4

Linked disclosures

Regulatory filings (10) · sorted by filing gap

Reporting entityMGM RESORTS INTERNATIONAL

Victim entityMGM RESORTS INTERNATIONAL

Incidentdiscovered Sep 29, 2023

Stated responseShutting down certain systems

ComplianceWA AG ≤30d

Extraction provenanceno artifact recorded

Source provenanceagportal-s3bucket.s3.amazonaws.com