A Browser Helper Object (BHO), is a small program that runs automatically every time the Internet Explorer browser is opened. These programs, .DLL modules, are designed as plugins to provide added functionality. For example, the Adobe Acrobat plugin that enables IE users to read PDF documents within their browsers is a Browser Helper Object. Because Browser Helper Objects have unrestricted access to Internet Explorer, some forms of Malware are created as Browser Helper Objects. For example, one type of malicious Browser Helper Object can activate upon detecting a secure HTTP connection to a bank or e-commerce site, record the user's keystrokes and then transmit the information to the Web site of the criminals who created it. Other Browser Helper Objects can track users' browsing patterns and pass the information they record to unauthorized third parties. Once installed, malicious Browser Helper Objects are very difficult to remove because they rarely include a functional uninstall utility. They could even attempt to "lock" the user out of Internet Explorer's configuration screens. These aggressive Browser Helper Objects render unavailable the Internet Explorer options required to remove the malicious software. Not all Browser Helper Objects are malicious. Many legitimate Browser Helper Objects enable Internet Explorer users to search the Internet directly from the browser's window, thus benefit from additional functionality. |