Cisco Cisco Email Security Appliance C190 Guida Utente
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Cisco IronPort AsyncOS 7.5 for Email Advanced Configuration Guide
OL-25137-01
Chapter 6 Using Message Filters to Enforce Email Policies
After you configure AsyncOS for image analysis, you can use image analysis
filter rules to perform actions on suspect or inappropriate emails. Image scanning
allows you to scan the following types of attached files: JPEG, BMP, PNG, TIFF,
GIF, TGA, ICO, and PCX. The image analyzer uses algorithms that measure skin
color, body size and curvature to determine the probability that the graphic
contains inappropriate content. When you scan image attachments, IronPort
fingerprinting determines the file type, and the image analyzer uses algorithms to
analyze the image content. If the image is embedded in another file, the Stellent
scanning engine extracts the file. The Stellent scanning engine can extract images
from many file types, including Word, Excel, and PowerPoint documents. The
image analysis verdict is computed on the message as a whole. If the message
does not include any images, the message receives a score of “0” which maps to
a “clean” verdict. Therefore, a message without any images will receive a "clean"
verdict.
filter rules to perform actions on suspect or inappropriate emails. Image scanning
allows you to scan the following types of attached files: JPEG, BMP, PNG, TIFF,
GIF, TGA, ICO, and PCX. The image analyzer uses algorithms that measure skin
color, body size and curvature to determine the probability that the graphic
contains inappropriate content. When you scan image attachments, IronPort
fingerprinting determines the file type, and the image analyzer uses algorithms to
analyze the image content. If the image is embedded in another file, the Stellent
scanning engine extracts the file. The Stellent scanning engine can extract images
from many file types, including Word, Excel, and PowerPoint documents. The
image analysis verdict is computed on the message as a whole. If the message
does not include any images, the message receives a score of “0” which maps to
a “clean” verdict. Therefore, a message without any images will receive a "clean"
verdict.
Note
Images cannot be extracted from PDF files.
To enable image analysis from the GUI:
Step 1
Go to Security Services > IronPort Image Analysis.
Step 2
Click Enable.
A success message displays, and the verdict settings display.
Figure 6-3
IronPort Image Analysis Overview
The image analysis filter rule allows you to determine the actions to take based on
the following verdicts:
the following verdicts:
•
Clean: The image is free of inappropriate content. The image analysis verdict
is computed on the message as a whole, so a message without any images will
receive a "clean" verdict if scanned.
is computed on the message as a whole, so a message without any images will
receive a "clean" verdict if scanned.
•
Suspect: The image may contain inappropriate content.