With all the Internet attacks that exploit Adobe Acrobat Reader people should switch to using an alternative PDF reader, a security expert said at the RSA security conference on Tuesday.

Of the targeted attacks so far this year, more than 47 percent of them exploit holes in Acrobat Reader while six vulnerabilities have been discovered that target the program, Mikko Hypponen, chief research officer of security firm F-Secure, said in a briefing with journalists.

Just last month, Adobe iss...