Pierce County Library System reports data breach affecting Over 335,000 individuals

The Pierce County Library System said the data security incidents it suffered earlier this year compromised the sensitive personal information of more than 335,000 individuals.

 

Serving Pierce County in Washington, Pierce County Library System has 19 libraries,  providing access to a wide range of materials, including books, movies, and online resources, to residents of the county.

 

In a data security incident notice on its website, PCLS said that earlier this ear, it identified suspicious activity within its internal network. The library officials immediately launched an investigation, with assistance from external cyber security experts, to determine the nature and scope of the incident.

 

It also took steps to secure the affected network and notified relevant law enforcement authorities about the same.

 

“The investigation determined our environment was subject to unauthorised access and between April 15 and April 21, 2025, certain files were copied and taken,” PCLS said.

 

The compromised data included names, dates of birth and other personal identifiable information. The data security incident notice also states that PCLS has identified at least 335,868 Washington residents impacted by the incident.

 

PCLS has advised all affected individuals to regularly monitor their credit reports, account and benefit statements and report any suspicious activity to law enforcement authorities, including the police and the state attorney general.

 

It has also offered one year of complimentary identity protection and credit monitoring services through IDX to all affected individuals.

 

 

In May, the INC Ransom ransomware group claimed responsibility for the cyber attack on PCLS and listed it as a victim on its data leak site. The group claimed to be in possession of 1.94 TB of confidential data stolen from the library. To prove the authenticity of its claims, the group shared data samples containing driver’s licenses, passports, and internal library documents.

 

It is not clear whether PCLS engaged with the hackers or paid a ransom to regain access to the stolen data.