Sirefef is a dangerous family of trojans that are all different and have their own tasks. They may not only block your firewall, but download malicious files on your computer, interrupt with annoying alerts and cause browser redirections. Because of sirefef.ac or sirefef.ah , you can find yourself on commercial domains that generate money through pay-per-click campaigns and may lead to malware infiltration. You must keep in mind that it is very important to remove Sirefef Trojans from the system, so do this as soon as possible.
According to security experts, Sirefef is one of the mostly spread malwares in the world at this moment. Many users don't even know that they have been infected with Win64/Sirefef.B or other trojan from this family and ignore such obvious signs of infection as Internet connection problems or continuous redirections when browsing the web. So, if your search is redirected, you should check your PC with reputable anti-malware program and remove these trojans.
If kept on the system, Sirefef will continues initiating havoc on it: it has been reported to delete the files found on the system, track sensitive user's information and even open a remote control connection to the PC. So, you can lose your passwords, financial information and money thanks to this rogue!
As you can clearly see, you must remove Sirefef from your computer. If you think you may have any of trojans from this family, find more information about its removal HERE .