Most owners of compromised websites don't know how their sites got hacked into and only 6 percent detect the malicious activity on their own, according to a report released by StopBadware and Commtouch on Thursday.

The new "Compromised Websites: An Owner's Perspective" report is based on a survey of over 600 website administrators and owners that was carried out over several months by security vendor Commtouch and StopBadware, a nonprofit organization that helps webmasters identify, remediate and prevent website compromises.

The leading cause of website compromises appears to be outdated content management software (CMS). This was indicated as a reason for their websites being hacked by 20 percent of respondents.

Twelve percent of webmasters said that a computer used to update their website was infected with malware, 6 percent said that their credentials were stolen credentials, and 2 percent admitted logging in while using wireless networks or public PCs. However, 63 percent of respondents didn't know how their websites got compromised.

The CMS platform most commonly installed on compromised websites was WordPress, as indicated by 28 percent of respondents. However, WordPress accounts for over 50 percent of the entire CMS market according to data from w3techs.com, so the rate between hacked WordPress websites and the platform's actual install base is better than that of other CMS platforms like Joomla or osCommerce.

Almost half of respondents -- 49 percent -- learned that their websites had been compromised through browser or search engine alerts. Eighteen percent were notified by their colleagues or friends, 10 percent by a security organization and 7 percent by their hosting provider. Only 6 percent of respondents discovered the compromise on their own by noticing suspicious or increased activity on their websites, the report said.

A third of respondents didn't know how their websites had been abused after being hacked. Those that did know pointed to the hosting of malware and rogue redirect scripts as being the most common forms of abuse -- 25 percent and 18 percent, respectively.

Many webmasters -- 46 percent -- managed to fix the compromise on their own, using information available on help forums and other websites. Twenty percent fixed the problem by following instructions received from security companies and 14 percent with the help of their hosting providers.

However, more than a quarter of respondents indicated that their websites remained compromised after trying several approaches.

Overall, 28 percent of webmasters said that they are considering switching Web hosting providers after their hacking experience. The survey found that webmasters were three times more likely to consider leaving Web hosting providers that charged extra for helping them address the problem or refused to provide support.

The report concluded that many webmasters are not fully aware of the threats their websites are exposed to and how to deal with possible compromises. Taking basic security precautions like keeping CMS software and plug-ins up to date, using strong and varied passwords that aren't stored on local machines, and regularly scanning computers for malware can go a long way to prevent website hacking incidents, the report said.

Improved methods of proactively notifying webmasters that their websites have been hacked are needed to complement browser and search engine alerts. Web hosting providers have an opportunity to strengthen the reputation of their brands by educating and helping customers whose websites have been hacked, the report said.