Tenet Healthcare, one of the U.S.'s largest for-profit hospital chains, is recovering from a "cybersecurity incident" that occurred last week, the company said Tuesday.
Dallas-based Tenet's investigation into the incident is ongoing.
Tenet identified unauthorized activity on some of its information-technology applications last week, the company said in a notice posted online. Tenet suspended access to the affected applications and "executed extensive cybersecurity protection protocols" to restrict further unauthorized access, the company said.
A Tenet spokesperson declined to comment on when Tenet detected the unauthorized activity, what applications were affected, how long applications were down, how many facilities had applications taken offline and what back-up processes Tenet implemented during that time.
"We don't have any comment beyond the press release," the spokesperson said via email.
WPTV-TV, an NBC affiliate in West Palm Beach, Florida, reported a network outage had brought down phone and computer systems at two Tenet facilities in Florida—St. Mary's Medical Center and Good Samaritan Medical Center—last week, during which clinicians reportedly had to turn to paper charts.
Critical applications have "largely been restored," and affected facilities have resumed normal operations, according to Tenet's public notice.
Tenet said in its notice said there was "temporary disruption to a subset of acute care operations," but that hospitals continued to operate and deliver patient care.
Staff at affected hospitals used back-up processes while IT applications were down.
"The company is taking additional measures to protect patient, employee and other data, as appropriate, in response to this incident," Tenet said in the notice. "Tenet is grateful to its physicians, nurses and staff for their dedication to safely care for patients as the company works to resolve this matter."
Federal agencies have put out numerous warnings in recent months, urging organizations to prepare for and protect against cyberattacks.
The Health Sector Cybersecurity Coordination Center, a center in the Health and Human Services Department's Office of Information Security, last week warned healthcare and public health organizations to guard against an "exceptionally aggressive" ransomware group, known as Hive, that encrypts and steals data from its victims.
The U.S. Cybersecurity and Infrastructure Security Agency last week issued a joint alert with cybersecurity authorities from four other countries to warn that Russia's invasion of Ukraine could lead to more "malicious cyber activity" in response to "unprecedented economic costs imposed on Russia" and "material support provided by the United States and U.S. allies and partners."
The White House in March warned there was "evolving intelligence that Russia may be exploring options for potential cyberattacks."
