Users of Yahoo Inc.'s e-mail service, Google Inc.'s Orkut social networking site and eBay Inc.'s PayPal online payment service were among the targets of attacks in recent weeks. All three companies have acknowledged and plugged the security holes.
The attacks come as Microsoft Corp., whose Windows operating system runs about 90 percent of the world's computers, has plugged many of the most easily exploited holes in its e-mail program, browser and other products following dozens of embarrassing breaches over the past several years.
