HackingConstructionConstructionStolen CredentialsEmployee Data InvolvedIdentity (basic)Government IDHealth (basic)EmploymentMediumContained

KIEWIT CORPORATION

bd_8983582f29524d82 · schema v1 · pii pii-v2

Severity

Medium

Discovered

—

Filed

Aug 1, 2026

To disclose

—

Affected

Not disclosed

Confidence

67%

Full breach record for KIEWIT CORPORATION →

Kiewit Corporation notified current and former employees/contractors of unauthorized access to an employee's Microsoft 365 account. The incident involved potential exposure of names, addresses, dates of birth, SSNs, driver's license numbers, and health information. Kiewit contained the incident by resetting passwords and disabling the account, engaged forensic investigators, and offered credit monitoring.

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Incident timeline — partial

? — ?

Breach window unknown

Aug 1, 2026

Filed

—

No filing yet · watching

Compliance clocks stay unassessable until a regulatory filing lands. Dashed segments fill in automatically when corroboration arrives.

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

Name: KIEWIT CORPORATION
norm: kiewit

Name: KIEWIT CORPORATION
norm: kiewit
Industry: Constructionllm

Discovered: —
Materiality determined: —
Notification sent: Aug 21, 2026
Affected individuals: Not disclosed
Data types: Identity (basic)Government IDHealth (basic)Employment
Attack vector: Unauthorized Access
MITRE ATT&CK: T1078 Valid AccountsT1114 Email Collection
Threat actor: External
Regulator citations: Notified law enforcement
Initial access: valid_credentials

During the incident: Launched an investigation
Engaged outside counsel
Retained a third-party forensic firm
Notified law enforcement
Implemented containment measures to prevent further unauthorized activity
Forced a password reset
Disabled the email account
Performed a comprehensive review to identify individuals potentially affected
Changes made: Taken several steps to enhance its security and monitoring practices
Further strengthen its systems to help prevent incidents like this from occurring in the future
Offered complimentary identity theft protection and credit monitoring services
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://www.mass.gov/doc/2026-1405-kiewit-corporation/download
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Aug 1, 2026
Raw hash: 583bb84acc5d77868fb8e3b077007ce3a300afa45cefbb84a1dbfb681a9bee8c

Reporting entityKIEWIT CORPORATION

Victim entityKIEWIT CORPORATION

IncidentUnauthorized Access

Stated responseLaunched an investigation

Complianceclock not assessable

Extraction provenanceno artifact recorded

Source provenancewww.mass.gov