The rules will be the first major updates to the one-year-old Payment Card Industry (PCI) data security standard, which analysts said is slowly but surely being adopted.

One set of PCI extensions is aimed at protecting credit card data from emerging Web application security threats, said Eduardo Perez, vice president of corporate risk and compliance at Foster City, Calif.-based Visa. Other new rules will require companies to ensure that any third parties that they deal with, such as hosting providers, have proper controls for securing credit card data.

Merchants who fail to comply with PCI can face fines or be excluded from processing credit cards.

The standard lists 12 broad controls that retailers, online merchants, data processors and other businesses must implement to protect cardholder data. They include technology controls such as data encryption, end-user access control and activity monitoring, as well as procedural mandates.

Most existing PCI requirements focus on security at the network level, but many of the latest threats are on the application side, said Philippe Courtot, CEO of Qualys Inc., a Redwood Shores, Calif.-based provider of managed security services. So it makes sense to update PCI to protect against Web application threats such as SQL injection attacks, cross-site scripting flaws, error-handling problems and validation errors, he said.