A browser hijacker is a malware program that changes the webpages your computer‘s browser opens to other than you wanted to visit. This might be done by malware process itself or changing browser settings. Usually it affects webpages you visit most often, e.g. home page and/or search pages, redirecting from them to their customers‘pages and subsequently generating a bigger trafic to the latter. For example, Happili redirect virus instead of your search browser‘s results opens its webpage and makes it almost impossible to complete any search. A more serious damage is when a browser hijacker adds bookmarks for pornographic websites to your own bookmark collection and generates pornographic pop-ups. Such redirects may lead to the pages with more viruses and infect your computer with malwares like Trojan or Rootkit.
Your computer may be infected with a browser hijacker either with or without your permission. It may be installed as part of freeware installation. Most likely this unwanted program is mentioned in the user agreement but not identified as a browser hijacker. Of course, most of the computer users do not read such agreements therefore they install the hijacker without realising about it. Without a user permission it might be installed via an infected e-mail, a file share or a drive by download. Happili redirect is a good example of a virus that infects a user‘s computer without his/her permission.
To protect your computer from this malware you should follow the general rules of safe computer usage: read user agreements carefully and be cautious about downloads and e-mails from unknown addresses. Additionally, you should install and use an antivirus program that offers real time protection.
But what if your computer is already infected and webpage browsing is annoing because of pop-ups, slower internet connection than usual, redirecting to the addresses that you are not interested at all? That depends on type of hijacker. Some hijackers can be removed manually easily. However, for some it is nearly imposible. Each browser hijacker has different manual removal instructions and a mistake might damage computer. In any case, you should identify the exact cause of hijacked browser by searching for more information or scanning with anti-malware programs.