The second largest cellular provider in the United States, AT&T, issued an apology to users of the Apple iPad whose email addresses were leaked last week during a security breach. Hackers were able to discover the email addresses of nearly 114,000 iPad 3G users through a program on AT&T’s website. Among the email addresses uncovered by hackers were those belonging to members of the U.S. military as well as executives at media, technology and finance companies.

New York Times Chief Executive Officer Janet Robinson and New York Mayor Michael Bloomberg’s email addresses were among those discovered by hackers. The group that uncovered the email addresses compiled them into a list to be sold in order to benefit their own publicity. Gawker Media’s Valleywag website was among a handful of places that received the hacked list of emails.

Goatse Security, which helps Web firms with security issues, discovered the gap in security on AT&T’s website. The company found the problem in a matter of an hour and publicized their results in the interest of iPad users’ safety. Dorothy Attwood, AT&T’s chief privacy officer, sent an e-mail on Sunday to the affected iPad accounts expressing the company’s regret and “apologizing for the incident and any inconvenience it may have caused.” The company insured those affected that no other information was obtained by the hackers.

The Federal Bureau of Investigation has opened an inquiry into the matter and has asked groups, such as Gawker Media, who received the hacked email lists to save any documents they received so they could be used in the investigation.