Joe's Spyware scanner is written with the purpose of detecting any vulnerabilities possible to detect over the web without the use of plugins.
The scanner checks for the existance of over 1000 known bad BHOs (Browser Helper Objects),
scans the operating system version and checks for the existance of known critical OS updates. Lastly,
it checks for a popup blocker and a hardware "NAT" Router. It accomplishes all of this using only
Javascript, Jscript and Java, and will function with Java disabled.
It scans for the BHOs by using a list of known bad BHOs. It attempts instanciate each bad BHO,
and if it succeeds, then it knows that the browser is infected with the BHO. If the BHO does not load, it is clean.
Next, it attempts to open a popup window. It then communicates with the popup window,
and if the communication works, it knows that a popup blocker is not installed. Next, it checks
the UserAgent string in IE, and uses that string to extrapolate the operating system version and service pack level.
Lastly, a Java applet compares the IP on your machine with the IP that the server is presented. If those numbers
are equal, then NAT translation is not occuring, otherwise it knows that a NAT router is installed. Lastly
the results are compiled and showed to the user using Javascript.
Unlike a traditional virus/spyware scanner, it does not have access to any of the files on your hard drive, and therefore can only detect specific types of threats.
NOTE: This site does not include instructions on fixing every vulnerability that it detects.