More than 50 of The UPS Store's U.S. locations were found to have malware on their computer systems, and in some cases, it's been present since mid-January.

Following an investigation by the company and an unnamed IT security firm, the majority of the affected shipping and printing stores were exposed to the malware since March 26, according to a release. Fifty-one locations in 24 states were targeted, which comprises about one percent of UPS' U.S. locations.

The malware was completely removed by August 11. Customers' names, addresses, email addresses and payment card information might have been exposed. Victims can receive free identity protection and credit monitoring services for one year.

The affected stores are listed online. The U.S. government sent out a bulletin to various retailers, including UPS, warning them of the possible malware presence.