HackingTelecom & MediaInformationStolen CredentialsCustomer Data InvolvedTargetedIdentity (basic)PIIHighContained

T-MOBILE USA, INC.

bd_f40ddf274a2800d7 · schema v1 · pii pii-v1

Severity

High

Discovered

Jan 5, 2023

Filed

Jan 19, 2023

To disclose

14 days

Affected

772,593state residents only

Confidence

69%

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

T-Mobile USA reported unauthorized access to customer account information in Washington. The breach, discovered on Jan 5, 2023, affected names, contact details, and DOBs. Passwords and SSNs were not compromised. 772,593 Washington residents were notified.

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Leak gap clock✗ Leak >180d14 days discovery → filing

⚠ AG web formThe discovery date came from the AG web-form field, which is systematically later than the detection date stated in the letter. Treat the clock as indicative.

Incident timeline

undetected · 41 days

discovery → filing · 14 days

Nov 25, 2022

Begins

Jan 5, 2023

Discovered

Jan 19, 2023

Filed

Tracked as a single-filing incident — the only disclosure on record for this event so far.Confirmed772,593 affectedView incident

A leak claim by arvinclub about this victim predates this filing by 497 days.View originating leak claim

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: Jan 5, 2023
Breach occurred: Nov 25, 2022 – Jan 5, 2023
Undetected for: 41 daysoccurrence → discovery
Materiality determined: —
Notification sent: Feb 7, 2023
Affected individuals: 772,593state-resident count only
Data types: Identity (basic)PII
Data elements: NameDate of birth
WA-stated cause: Unauthorized Access
WA-stated duration: lifecycle 1-99dexposure 1-99d
WA-stated discovery: Found while ongoingContained same day
Attack vector: Unauthorized Access
MITRE ATT&CK: T1078 Valid Accounts
Threat actor: ExternalFinancial
Regulator citations: Notified Washington State Attorney General
Initial access: valid_credentials

During the incident: Sent notification letters to affected individuals
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 14 days(14 days from discovery to filing)
Compliance flags: Leak >180dWA AG ≤30d
Discovery-date grounding: AG web formThe discovery date came from the AG web-form field, which is systematically later than the detection date stated in the letter. Treat the clock as indicative.

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://agportal-s3bucket.s3.amazonaws.com/databreach/BreachA17480.pdf
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Jan 19, 2023
Raw hash: ca1ce49c6efa2bede3378aa97d1c38e89eae1da1bcb04d7e40a59fc2452e01a0

Reporting entityT-MOBILE USA, INC.

Victim entityT-MOBILE USA, INC.

Incidentdiscovered Jan 5, 2023

Stated responseSent notification letters to affected individuals

ComplianceLeak >180d

Extraction provenanceno artifact recorded

Source provenanceagportal-s3bucket.s3.amazonaws.com