HackingFinancial ServicesTechnologyFinanceData ExfiltratedCustomer Data InvolvedIdentity (basic)Government IDFinancial accountMediumContained

Guggenheim Partners LLC

bd_3a168968bea76911 · schema v1 · pii pii-v1

Severity

Medium

Discovered

Dec 1, 2021

Filed

Jun 27, 2022

To disclose

30 weeks

Affected

3state residents only

Confidence

66%

Full breach record for Guggenheim Partners LLC →

MUFG Investor Services (US), LLC notified affected individuals of a data breach involving its third-party service provider, R.R. Donnelley & Sons Company (RRD). RRD detected unauthorized access in late December 2021, which resulted in the exfiltration of personal information including names, addresses, SSNs, and account numbers. MUFG is offering 24 months of credit monitoring. The incident is contained.

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Incident timeline

discovery → filing · 30 weeks / 208 days

Dec 1, 2021

Discovered

Jun 27, 2022

Filed

vs. sector median

+21 wks slower

Tracked as a single-filing incident — the only disclosure on record for this event so far.Confirmed3 affectedView incident

Name: MUFG Investor Services (US), LLC
norm: mufg investor services us

Name: Guggenheim Partners LLC
norm: guggenheim partners
Industry: Financial ServicesllmTechnologyllm

Discovered: Dec 1, 2021
Materiality determined: —
Notification sent: Jun 24, 2022
Affected individuals: 3state-resident count only
Data types: Identity (basic)Government IDFinancial account
Data elements: Social Security number
Attack vector: Unauthorized Access
MITRE ATT&CK: T1078 Valid AccountsT1041 Exfiltration Over C2 Channel
Threat actor: External

During the incident: RRD took immediate action to isolate the attack and secure its systems
RRD notified law enforcement
RRD performed an assessment of these data files
Changes made: RRD implemented enhanced security measures to help further protect against this type of incident going forward
Offered complimentary access to Experian's IdentityWorks for 24 months
Source: Quoted from the filing itself, not independently verified.

Time to disclose: 30 weeks(208 days from discovery to filing)
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/Consumer-Notification-Letter-376.pdf
DisclosureLens links to the originating regulator URL — full filing bodies are not redistributed from public surfaces (§4.5).
Filed at: Jun 27, 2022
Raw hash: ba1b207fbc2f0c3fcea32f07387c56d73c4146032e1587315889d092f86e8aa6

Reporting entityMUFG Investor Services (US), LLC

Victim entityGuggenheim Partners LLC

Incidentdiscovered Dec 1, 2021

Stated responseRRD took immediate action to isolate the attack and secure its systems

Complianceclock not assessable

Extraction provenanceno artifact recorded

Source provenancedojmt.gov