A study of 57 Web site hacks from last year showed that 24 percent were aimed at defacing a site rather than financial gain.
The figures from the latest Web Hacking Incidents Database Annual Report suggest that stealing money and data is not always the overriding motivation for hackers, although it has been a rising trend in recent years.
"While financial gain is certainly a big driver for Web hacking, ideological hacking cannot be ignored," the report said, which was sponsored by vendor Breach Security with support from the Web Application Security Consortium.
Although there were hundreds of thousands of Web site attacks in 2008, the report set a strict criteria for its analysis: It looked at only those incidents that were publicly reported, were associated with Web application security problems and had an identifiable impact on an organization.
These criteria allow people to understand the potential business impacts as opposed to just the technical failure, which is important in order to manage risk, the researchers said.
Web site vandalism may carry a lower risk for organizations than a financial attack, but still highlights insecure Web pages.
The report found the majority of defacements "were of a political nature, targeting political parties, candidates and government departments, often with a very specific message related to a campaign. Others have a cultural aspect, mainly Islamic hackers defacing Western Web sites."
Government, law enforcement and political Web sites were the most targeted categories of Web sites.
The second most popular motivation was stealing sensitive information, which occurred in 19 percent of the 57 hacks. That was followed by planting malware, at 16 percent, and causing monetary loss, at 13 percent.
The remaining attacks caused downtime for a Web site, planted worms and linked spam and information warfare.
The most common style of attack was SQL injection, which involves inputting commands into Web-based forms or URLs (Uniform Resource Locators) in order to return data held in back-end databases or plant malware in order to infect computers visiting the site. Thirty percent of the 57 attacks were carried out by SQL injection.
In early 2008, security experts were stunned by a wave of attacks that used automated tools to seek out weak Web sites to compromise by SQL injection. It has been estimated that up to 500,000 Web sites fell victim to hacks.
SQL injection attacks subsequently displaced cross-site scripting as the most common attack method. A cross-site scripting flaw can allow data or malicious code to be drawn from another a Web site, which can potentially cause a data breach.
Cross-site scripting flaws are easier to find but it is "somewhat harder to take advantage of them for profit-driven attacks," indicating a cause for the surge in SQL injection, the report said.