HackingTelecom & MediaInformationStolen CredentialsSupply Chain (3P Vendor)Customer Data InvolvedIdentity (basic)Government IDFinancial accountMediumContained

T-MOBILE USA, INC.

bd_38790afeebf7592d · schema v1 · pii pii-v1

Severity

Medium

Discovered

—

Filed

Mar 10, 2020

To disclose

—

Affected

1state residents only

Confidence

66%

Full breach record for T-MOBILE USA, INC. →22 incidents on file

T-Mobile USA notified Montana AG of a breach affecting customer and employee email accounts via a compromised email vendor. Unauthorized access occurred Nov 26–Dec 25, 2019. Data included names, addresses, SSNs, financial account info, and government IDs. T-Mobile engaged forensic experts, notified law enforcement, and offered credit monitoring.

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Incident timeline

Nov 26, 2019

Begins

Mar 10, 2020

Filed

Tracked as a single-filing incident — the only disclosure on record for this event so far.Confirmed1 affectedView incident

Name: T-MOBILE USA, INC.
norm: t mobile usa
Domain: t-mobile.com

Name: T-MOBILE USA, INC.
norm: t mobile usa
Domain: t-mobile.com
Industry: Telecom & Mediallm

Discovered: —
Breach occurred: Nov 26, 2019 – Dec 25, 2019
Materiality determined: —
Notification sent: —
Affected individuals: 1state-resident count only
Data types: Identity (basic)Government IDFinancial account
Data elements: Social Security number
Attack vector: Third-Party / Supply Chain
MITRE ATT&CK: T1195 Supply Chain CompromiseT1078 Valid Accounts
Threat actor: ExternalFinancial
Regulator citations: Reported matter to federal law enforcement
Initial access: supply_chain

During the incident: Identified and shut down a malicious attack against our email vendor
Commenced an investigation with assistance from leading cybersecurity forensics experts
Reported this matter to federal law enforcement
Offering free credit monitoring and identity theft detection services provided by TransUnion
Changes made: Enhancing security to stay ahead of this type of activity
Source: Quoted from the filing itself, not independently verified.

Compliance flags: — (clock not assessable for this source)

Status: No extraction artifact recorded for this disclosure.

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://dojmt.gov/wp-content/uploads/OCP/Breach-NotificationDetails-130.pdf
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Mar 10, 2020
Raw hash: 70cfed73f4d81eed75c9dfe1febccc0707a9e27854d2482e27702709bce0ebb4

Reporting entityT-MOBILE USA, INC.

Victim entityT-MOBILE USA, INC.

IncidentThird-Party / Supply Chain

Stated responseIdentified and shut down a malicious attack against our email vendor

Complianceclock not assessable

Extraction provenanceno artifact recorded

Source provenancedojmt.gov