Intruders used IDs and passwords of legitimate customers of LexisNexis' Seisint unit and may have acquired sensitive data such as Social Security numbers and driver's license numbers of U.S. residents, the data broker said in a statement released Tuesday.
There were about 59 incidents of this fraudulent activity, the company said. Law enforcement officials are investigating the case.
Last month, LexisNexis notified about 30,000 individuals of the breach. Now it is sending notices to 280,000 additional people. No one from the initial group has reported identity theft, the company said.
LexisNexis and Seisint said they are taking steps to improve security of customer passwords and ID administration. LexisNexis also is limiting access to Social Security numbers by extending its restrictive policies to the Seisint unit.