T-Mobile previously agreed to a$350 million settlementto resolve claims that its negligence led to the breach.
The Washington state lawsuit seeks additional penalties and changes to T-Mobile’s cybersecurity practices to prevent future breaches.
T-Mobile’s headquarters are in the Seattle suburb of Bellevue, Washington.
The lawsuit alleges that T-Mobile didn’t disclose enough information about what was compromised.
“This significant data breach was entirely avoidable,” Fergusonsaidin a press release.
“T-Mobile had years to fix key vulnerabilities in its cybersecurity systems and it failed.”
It also said it reached out to the office in late November to continue those conversations.
We’re always working to protect you and your family and keep your data secure."
Read more:I Use T-Mobile Home Internet Every Day.
