SP.exe - by Spigot, Inc.
What is SP.exe?
SP.exe belongs to Spigot adware. This adware comes bundled with browser hijackers and potentially unwanted programs. SP means Search Protection, so as the name suggests it protects something related to your search engine provider. And indeed, this program runs in the background and constantly checks for search engine provider and other browser settings modifications. The bad news is that it doesn't protect your default home page or search engine provider like Google or Bing. It protects a browser hijacker that came bubdled with Spigot adware. In other words, SP.exe protection program is design to protect malicious browser modification made by adware and browser hijackers. If you try to change your home page or search engine provider back to default SP.exe will not allow you to do that or will change your browser settings back to previous state after you restart your computer. Different variants of this adware work in slightly different ways but the result is the same every time - your web browser remains hijacked. Unfortunately, most anti-virus engines do not detect SP.exe as malware. Only 4 out of 56 at the moment, according to VirusTotal. It's actually not surprising at all. Most anti-virus programs tend to miss such infections or ignore them because they are not malicious enough. They can't steal your passwords or delete your files. That's true but infections like SP.exe are still very annoying and difficult to get rid of. They are not essential for Windows and may cause some serious problems. I recommend you to remove this programs and related malware from your computer. Run a full system scan with anti-malware software.
File name: SP.exe
Publisher: Spigot, Inc.
File Location Windows XP: C:\Documents and Settings\[USERNAME]\Application data\search protection\
File Location Windows 7/8: C:\Appdata\[USERNAME]\search protection\
Startup file: HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run → SP.exe