McAfee VIRUSSCAN 5.1 User Manual page 115

To see or designate the file name extensions that the E-Mail Scan
module will examine, click Extensions to open the Program File
Extensions dialog box
Figure 4-20. Program File Extensions dialog box
• Scan all files. Select the All files button to have the E-Mail Scan
module examine any file, whatever its extension, whenever you or
a system process modifies it in any way.
5. Turn on heuristic scanning. Click Advanced to open the Advanced Scan
Settings dialog box
Figure 4-21. Advanced Scan Settings dialog box
Heuristic scanning technology enables the E-Mail Scan module to
recognize new viruses based on their resemblance to similar viruses that
the module already knows.
To do this, the module looks for certain "virus-like" characteristics in the
files you've asked it to scan. The presence of a sufficient number of these
characteristics in a file leads the module to identify the file as potentially
infected with a new or previously unidentified virus.
Because the E-Mail Scan module looks simultaneously for file
characteristics that rule out the possibility of virus infection, it will rarely
give you a false indication of a virus infection. Therefore, unless you
know that the file does not contain a virus, you should treat "potential"
infections with the same caution you would confirmed infections.
(Figure 4-10).
(Figure 4-11).
Using the VShield Scanner
User's Guide 115