2021-10-08 QUEST DIAGNOSTICS INC Cybersecurity Incident

Page last updated on September 23, 2025

QUEST DIAGNOSTICS INC initially disclosed a cybersecurity incident in an SEC 8-K filing on 2021-10-08 16:15:30 EDT.

Incident Details

Material: No
Is Breach: Yes
Records Compromised: 350,000
Data Types Impacted: Unspecified, Health data

Compromised Date: Unknown
Detected Date: Unknown
Disclosure Date: 2021-10-08
Contained Date: Unknown
Recovered Date: Unknown

Attack Goal: Unknown
Attack Tactics¹: TA0040, TA0010
Attack Techniques¹: T1486, T1041

Costs: No Costs Tracked (yet)

Filings

8-K filed on 2021-10-08

QUEST DIAGNOSTICS INC filed an 8-K at 2021-10-08 16:15:30 EDT
Accession Number: 0000947871-21-001054

Item 8.01 Other Events.

In August 2021, ReproSource, a subsidiary of Quest Diagnostics Incorporated, experienced a data security incident in which an unauthorized party may have accessed or acquired protected health information and personally identifiable information of ReproSource patients. Quest Diagnostics' systems were not impacted by this incident.

In connection with the incident, ReproSource discovered the presence of ransomware, quickly contained the ransomware, and securely restored operations. It also immediately launched an investigation and retained cybersecurity experts to determine the cause and scope of the incident, and promptly notified law enforcement.

While the investigation did not confirm that the unauthorized party acquired data in the incident, ReproSource has begun notifying individuals whose personal information may have been accessed. Based on its analysis to date, ReproSource estimates that data accessed may contain personal information of approximately 350,000 patients.

Quest Diagnostics maintains cybersecurity insurance and does not believe this incident will have a material impact on its business, results of operations or financial condition.

Company Information