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Mandiant

Controversies

Controversies tied to this brand in public sources. A listing is not a finding of fault.

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  1. 2026

    MyMichigan Health investigates cyberattack claims

    Company response

    MyMichigan Health stated that it is investigating a group's claim that it stole data. According to the organization, the investigation has so far found no unauthorized system access or compromise of patient information. MyMichigan Health also hired Mandiant to help assess the claims. The event was reported on October 16, 2026.

    MyMichigan Health says it is investigating a group's claim that it stole data, has found no unauthorized system access or compromise of patient information so far, and hired Mandiant to help assess the claims.

    Company response

    • Investigation — MyMichigan Health

      The health system began investigating immediately, and it hired Mandiant, an independent cybersecurity incident response firm, and is working with law enforcement to assess the claims.

    Source excerpt

    • The health system began investigating immediately, and it hired Mandiant, an independent cybersecurity incident response firm, and is working with law enforcement to assess the claims.
    • MyMichigan Health says its investigation so far has found no unauthorized access to its systems and no compromise of patient information.
    • A group calling itself MetaEncryptor claims it stole data from MyMichigan Health, but the health system says the group has offered no proof, including sample files.
    Source

  2. 2022

    News Corp discloses cyberattack affecting employee accounts and documents

    Issue disclosure

    News Corp disclosed that digital intruders broke into email accounts and compromised data belonging to a limited number of employees, including journalists. The company said the breach was discovered in late January, and Mandiant said it had contained the breach. Mandiant assessed that those behind the activity had a China nexus; the source reports that this was an assessment, not a determination of responsibility.

    Company response

    • Investigation — News Corp

      Upon discovering the attack, the company told law enforcement and hired cybersecurity firm Mandiant Inc. to assist with an investigation.

    • Ongoing disclosure — News Corp

      News Corp believes the threat is contained , and has been giving guidance to those affected by the attack.

    Source excerpt

    • News Corp, which publishes the Wall Street Journal, said the breach was discovered in late January and affected emails and documents of what it described as a limited number of employees, including journalists. It said that cybersecurity firm Mandiant had contained the breach.
    • Digital intruders broke into News Corp email accounts and compromised the data of an unspecified number of journalists, the company disclosed Friday
    • we believe the activity affected a limited number of business email accounts and documents from News Corp headquarters, News Technology Services, Dow Jones, News UK, and New York Post.
    Source

  3. 2021

    T-Mobile CEO addresses data breach and security response

    Company response

    In August 2021, T-Mobile CEO Mike Sievert spoke publicly after a data breach affecting more than 50 million people. He said the breach was contained and that the investigation was substantially complete. T-Mobile also said it was partnering with Mandiant and KPMG to improve security. The statements addressed the company's response to the incident and its planned security measures.

    Stated objective. tighten things up

    Company response

    • Ongoing disclosure — T-Mobile

      CEO Mike Sievert is speaking out.

    • Remediation — T-Mobile

      To do something about it, T-Mobile is partnering with cybersecurity firm Mandiant and consultants at KPMG to tighten things up.

    Source excerpt

    • Sievert says he’s taking a moment to update us now that the breach is contained and the investigation is “substantially complete.”
    • A recent T-Mobile data breach coughed up the information of more than 50 million people, including some who aren’t current customers or never were.
    • To do something about it, T-Mobile is partnering with cybersecurity firm Mandiant and consultants at KPMG to tighten things up.
    Source

  4. 2021

    Neiman Marcus discloses customer data breach

    Issue disclosure

    Neiman Marcus Group informed 4.6 million customers about a breach involving possible illegal access to personal information, including account credentials and payment details. The company said the breach took place in May 2020, reported the incident to law enforcement, and was working with Mandiant and law enforcement to investigate.

    Company response

    • Investigation — Neiman Marcus Group

      Along with the law enforcement, they are investigating the situation,

    • Ongoing disclosure — Neiman Marcus Group

      We will continue to take actions to enhance our system security and safeguard information.

    Source excerpt

    • It seems that the discovery was a little late, as the breach was said to have taken place in May 2020.
    • Neiman Marcus, an American chain of luxury department stores headquartered in Dallas, Texas, revealed on Thursday, Sept. 30, that it had alerted its online customers about the data breach.
    • We will continue to take actions to enhance our system security and safeguard information.
    Source