If your website is running on Joomla CMS, its time to check weather your site got compromised or not. No CMS system is perfect. There will be loopholes and security issues, some or known and some are unknown. The joomla developer team gives high priority to security. They are continuously working to get it better.
Many website owners who are running their site, does not aware that their website got hacked. Recently I have found many joomla based websites hacked their owners did not noticed it. The top reason for getting your site hacked is your joomla version is not up to date. It is pain in ass to update the joomla if your Joomla CMS is running on completely different version. What is mean is.. it is hard to migrate from joomla 2.5.x to 3.x or 1.5.x to 2.5.x. Due to this reason many joomla users are leaving their joomla sites as they are without migrating to newer version.
Fine, how does hackers come to know your joomla site is not upgraded and your site is running on Joomla? Why hackers targets only your site?
The answer to first question is simple. It is Google. Yes. Believe it. I will explain it later, but first lets check your site is hacked or not.
Please go to google.com and type site:yoursite.com (should be your site name)
Now see all the results. If you found something abnormal in your titles like “viagra” or “pharma” or “cialis” , it means your site got compromised.
If your site is big and it takes lot of time to find every title on google.. then try google this
You may find somethng like this
I found my site hacked. What now?
Migrate / Upgrade to latest version of Joomla.
Why hackers targets your site only?
They do not have a specific target. They will just use google to find out what are the websites running on joomla and target them.