Social EngineeringFinancial ServicesFinancePhishingStolen CredentialsCustomer Data InvolvedTargetedIdentity (basic)Government IDFinancial accountPIIMediumContained

Plains Commerce Bank

bd_7c8af5e8d5f5730e · schema v1 · pii pii-v1

Severity

Medium

Discovered

Jan 20, 2021

Filed

May 27, 2021

To disclose

18 weeks

Affected

218state residents only

Linked

7 filings

Confidence

65%

Full breach record for Plains Commerce Bank →

Plains Commerce Bank notified Montana residents of a data breach involving unauthorized access to employee email accounts. The incident occurred between Dec 10, 2020, and Jan 15, 2021. Affected data included names, addresses, SSNs, and financial account information. The bank engaged forensic investigators and offered 12 months of credit monitoring.

J jump to incidentP pin to compareR raw source

Incident timeline

undetected · 41 days

discovery → filing · 18 weeks / 127 days

Dec 10, 2020

Begins

Jan 20, 2021

Discovered

May 27, 2021

Filed

vs. sector median

+9 wks slower

This filing is one of 7 about the same incident.View merged incident

Linked disclosures

Why this link?

Regulatory filings (6) · sorted by filing gap

California State AGbd_0428b6dd3ebc05fc2021-05-27Verified
Maine State AGbd_0c2b14534f2a0dad2021-05-27Verified
Massachusetts State AGbd_2a861c05ece55b602021-05-27Verified
Indiana State AGbd_97a68cf8b20b6c812021-05-27Verified

Show 2 more filings ↓up to 146d gap

New Hampshire State AGbd_4b1061280c6de9ab2021-06-01 · +5dVerified
Illinois State AGbd_94edaa7272227ac72021-01-01 · +146dCandidate

Name: Plains Commerce Bank
norm: plains commerce bank
Domain: plainscommerce.com

Name: Plains Commerce Bank
norm: plains commerce bank
Domain: plainscommerce.com
Industry: Financial Servicesllm

Discovered: Jan 20, 2021
Breach occurred: Dec 10, 2020 – Jan 15, 2021
Undetected for: 41 daysoccurrence → discovery
Materiality determined: —
Notification sent: May 27, 2021
Affected individuals: 218state-resident count only
Data types: Identity (basic)Government IDFinancial accountPII
Data elements: Social Security number
Attack vector: Phishing
MITRE ATT&CK: T1566.002 Spearphishing LinkT1078 Valid AccountsT1114 Email Collection
Threat actor: ExternalFinancial
Initial access: phishing_link

During the incident: Launched an investigation to determine the nature and scope of the activity
Working with third-party forensic investigators
Immediately took steps to secure our systems
Undertook efforts to review the general types of information present in the email accounts
Offering complimentary credit monitoring and identity protection services for 12 months through Experian
Changes made: Implementing additional safeguards
Reviewing policies and procedures
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 18 weeks(127 days from discovery to filing)
Compliance flags: — (clock not assessable for this source)

Status: No extraction artifact recorded for this disclosure.

Filing propagation · 7 filings · 7 states

View merged incident ↗

Illinois State AGJan 1 · first

California State AG+146d

Maine State AG+146d

Massachusetts State AG+146d

Indiana State AG+146d

Montana State AG+146d · this page

New Hampshire State AG+151d

Pattern: first filing Jan 1 (IL), last Jun 1 (NH) — a 151-day rolling notification. Rolling spreads often mean counsel is filing as thresholds trip per state. Why this link?

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/Plains-Notif.pdf
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: May 27, 2021
Raw hash: a0078fb5d6ba799eaf6fecd2445cc9c3d2b5ed58c092d71ac4e7f4a673a4f5ee

Linked disclosures

Regulatory filings (6) · sorted by filing gap

Reporting entityPlains Commerce Bank

Victim entityPlains Commerce Bank

Incidentdiscovered Jan 20, 2021

Stated responseLaunched an investigation to determine the nature and scope of the activity

Complianceclock not assessable

Extraction provenanceno artifact recorded

Source provenancedojmt.gov