WordPress, Firefox and many open-source projects are great however, because of their open nature, they generally get targeted by hackers & notorious fellows. Its pretty important to keep your blog software up to date, if its based on any open-source code as the security breachers tend to attack on old codes.
There are various threats for WordPress and they can be easily become part of your WordPress blog with the help of plugins, themes and through various security vulnerabilities. To counter this, Sergej Muller has created a wonderful plugin that acts as an Antivirus for WordPress (english translation)!
(Photo Credit – Nirmal)
This plugin scans your WordPress theme for any sort of malicious injections and vulnerabilities on daily basis and lets you run the scan manually too. This is definitely a must have plugin for all of us as it’ll not only keep our blog safe but will also ensure that no other visitor will get infected from any such malicious activity.