ImageLogic

Secure Email Gateway detects and blocks images classified as unacceptable within messages. An unacceptable image is defined as either:

• An image that has been manually classified as unacceptable.
• An image that has been automatically classified by ImageLogic as unacceptable due to similarities with nude or pornographic images.

Detect unacceptable images

You can detect unacceptable images by adding a 'Detect Unacceptable Images' content rule to a policy route.

ImageLogic scans and classifies each image, rating it with an acceptability score. Unacceptable images can then be processed (typically quarantined) by the Detect Unacceptable Images content rule. Within this content rule, the sensitivity ImageLogic can be adjusted by defining a threshold value for acceptable images, or reverting to the system default threshold value.

Classify images

You can manually classify specific images as either acceptable or unacceptable and ImageLogic will use those classifications when those images are encountered within messages. A single image or a ZIP file containing several images can be uploaded and each of the images can then be marked as either Acceptable or Unacceptable. If an image is already classified, the existing classification will be displayed but this can be changed, if required. JPG, GIF, PNG and BMP image files are supported. See Upload images to ImageLogic for more information.

If an image has been incorrectly categorized as unacceptable by ImageLogic, you can manually reclassify the image as acceptable and reprocess the message. See Manage Held Messages for more information.

Access permissions

The administrator can control which users can view the images in a quarantined message by assigning privileges to view the Image tab when viewing a quarantined message in the Unacceptable Images Message Area. The administrator can control which other administrators can fine tune ImageLogic by assigning the 'Classify Images' privilege. See Users menu and related topics for more information.

Reset classification data

You can reset ImageLogic classification data which will remove all of the currently held data on the current peer. See Reset ImageLogic classification data for more information.

Peer Gateways

Image classifications can be used by all peered Gateways and, when an image is reclassified, the change will be sent to all peers in a peer group. Copying this information may take several minutes. See Replicate ImageLogic classification data to peers for more information.

Back up classification data

ImageLogic classification data can be backed up by selecting the Configuration System Area when performing a System Backup. See System Backup and Restore for more information.

The detection of unacceptable images is not guaranteed. Although the technology is constantly improving, it is a very complex subject and, therefore, the feature may generate occasional false positives. As with each content analysis feature, deploying ImageLogic will incur additional processing overhead, so consideration to the specification of the hardware and message volumes is important. Images in a Zip file may be in directories but not in a nested Zip. Zip (including *.zipx) is the only supported archive for uploading images. Image Classifications will be applied automatically; you do not need to apply the configuration for changes to take effect.

 

Upload images to ImageLogic

Specific images can be classified and ImageLogic will use those classifications when those images are encountered within messages.

A single image or a ZIP file containing several images can be uploaded and each of the images can then be marked as either Acceptable or Unacceptable. If an image is already classified, the existing classification will be displayed but this can be changed, if required.

Images can only be uploaded if you have the appropriate Classify images access permission. See Users menu and related topics for more information. Zip files with a Japanese filename or that contain files with a Japanese filename cannot be uploaded.

1. Navigate to Policy > Policy References > ImageLogic. The ImageLogic page is displayed.
2. In the Classify Images for ImageLogic panel, click Upload. The Upload Images For Classification dialog is displayed.

3. Click Choose file. Browse and select a required image, then click Open. JPG, GIF, PNG and BMP image files are supported.

4. Click Upload.
5. If the upload is successful, the Review Images dialog opens, displaying the uploaded image(s).

6. Specify whether the new image is acceptable or unacceptable.

   • Select the new image(s) using the check box.
   • To identify as acceptable, click Acceptable.
   • To identify as unacceptable, click Unacceptable.
   • Images are removed from the display when they have been classified.
   • When all of the images have been classified or the panel is closed, the Images Have Been Classified dialog opens showing the total number of images classified as acceptable or unacceptable.
   • Click OK to close the dialog.

7. Apply the configuration.

 

Reset ImageLogic classification data

You can reset the ImageLogic classification data which will remove all of the currently held data on the current peer.

1. Navigate to Policy > Policy References > ImageLogic. The ImageLogic page is displayed.
2. Click Reset ImageLogic classification data on the task panel. The Reset ImageLogic dialog is displayed.
3. Click the Reset to confirm that you wish to delete the classification data.
4. A dialog will be displayed confirming that the ImageLogic classification data was reset.
5. Click Close to close the dialog.

 

Replicate ImageLogic classification data to peers

You can replicate ImageLogic classification data to peers, if necessary. Replication of data is automatic but, if a peer has been offline, you may wish to refresh the classification data.

1. Navigate to Policy > Policy References > ImageLogic. The ImageLogic page is displayed.
2. Click Replicate ImageLogic classification data to peers on the task panel. The Replicate ImageLogic data dialog is displayed.
3. Click Replicate to confirm that you wish to replicate the classification data.
4. A dialog will be displayed confirming that the ImageLogic classification data was replicated.
5. Click Close to close the dialog.

The ImageLogic classification data on the peers will not be changed if you have reset the ImageLogic classification data and no new images have been added.

 

Set the threshold value for unacceptable images

ImageLogic rates the acceptability of each image it scans by assigning it a score based on its content. Higher scores are considered to be less acceptable than lower scores. Images scoring higher than the threshold value you've set are considered unacceptable and the appropriate action (typically quarantine) is applied by the content rule.

1. Add a Detect Unacceptable Images content rule to your policy.
2. In the What To Look For? panel, configure the Unacceptable Images section to set the threshold that is applied by ImageLogic.
3. Apply the configuration.

If you change any configuration or policy settings, you must Apply Configuration for the new settings to take effect. You can do this either from the Changes Made panel, or System > Configuration > Apply Configuration. See Apply new configuration for more information. If you use Peer Gateways (i.e. when multiple Gateways are peered), any configuration changes from a local Gateway can then be applied to all the peers at the same time. See Peer Gateways for more information.