By Karen Sloan and Mike Scarcella

July 6 (Reuters) - Blank Rome is the latest U.S. law firm to face a proposed class action for allegedly failing to protect clients’ sensitive personal information — including Social Security numbers — after hackers targeted the firm in a May data breach.

Law firms, like other major U.S. companies, have been increasingly targeted by cyberattacks in recent years. Law firms can be particularly attractive to hackers because they routinely store large volumes of sensitive client information, including financial, business and litigation-related records.

Here are the details:

• The lawsuit, filed Monday in Pennsylvania federal court, was brought by Laura Delapaz, a California resident who said in her complaint that she was among 57,554 current, former and prospective Blank Rome clients whose personal information was compromised in a May 21 data breach.

• Delapaz alleged the firm waited more than a month to disclose the breach to affected clients and that names, birth dates, addresses and taxpayer information numbers were among the compromised data.

• Blank Rome said in a statement Monday that it experienced a "limited incident" in which a "group that targets law firms" called one of its attorneys posing as the firm’s IT department and misled the lawyer into uploading files to an external file hosting website.

• "We believe the lawsuit has no merit and will aggressively defend against it," the firm said.

• Delapaz’s attorneys with Chicago firm Strauss Borrelli did not immediately respond to requests for comment Monday. The lawsuit alleges Blank Rome “failed to adequately train its employees on cybersecurity and failed to maintain reasonable security safeguards or protocols.”

• A growing number of law firms have faced similar data breach lawsuits. Fox Rothschild; Wiley Rein; Pillsbury; and Kelley Drye are among the firms that have been sued in the past year. Some firms, including Gunster Yoakley & Stewart, Orrick Herrington & Sutcliffe, and Bryan Cave Leighton Paisner, have reached settlements in recent ⁠years.