Suspected Malware policies detect and prevent against zero day malware (malware where specific antivirus software signatures aren't yet available) and spam outbreaks. These checks provide protection against previously unknown threats, using deep level anomaly detection and trending. Suspected Malware Bypass policies allow you to configure certain mail flows to bypass these default malware checks.
Consider the following before configuring a policy:
- A Suspected Malware Bypass policy must only be configured if regular attachments are being blocked that need to be allowed through. Bypassing malware checks in other circumstances can result in a new virus outbreak going undetected whilst signatures are being updated.
- Messages containing compressed (.ZIP) attachments that themselves contain an .EXE, .COM, .PIF, .SCR, .CPL, or .MSI file, are placed in the hold queue and marked as suspected malware. The intended recipient is sent a notification, and must ask an administrator to release the message.
- Encrypted compressed (.ZIP) files cannot be checked by a suspected malware policy. For this scenario we recommend using an Attachment Management Policy.
- Messages placed in the hold queue due to a “Suspicious Message Structure”, indicates that they has not been correctly structured. This is based on RFC822 and RFC1123 (Request for Comment) documents, published by the Internet Engineering Task Force (IETF). Whilst many mail servers and clients do not conform to these RFC standards, we are ﬂexible on the format we accept, and therefore only hold problematic occurrences.
Configuring a Suspected Malware Bypass Policy
To configure a Suspected Malware Bypass policy:
- Log on to the Administration Console.
- Click on the Administration menu item. A menu drop down is displayed.
- Click on the Gateway | Policies menu item. The Gateway Policy Editor is displayed.
- Click on Suspected Malware Bypass. A list of policies is displayed.
- Either select the:
- Policy to be changed.
- New Policy button to create a policy.
- Complete the Options section as required:
Option Description Policy Narrative Provide a description for the policy to allow you to easily identify it in the future. Select Option
Select whether to hold or ignore suspected malware.
- Complete the Emails From and Emails To sections as required:
Field / Option Description Addresses Based On Specify the email address characteristics the policy is based on. This option is only available in the "Emails From" section. The options are: Option Description The Return Address (Mail Envelope From) This default setting applies the policy to the SMTP address match, based on the message's envelope or true address (i.e. the address used during SMTP transmission). The Message From Address (Message Header From) Applies the policy based on the masked address used in the message's header. Both Applies the policy based on either the Mail Envelope From or the Message Header From whichever matches. If both match the specified value the Message Header From is used. Applies From / To Specify the Sender characteristics the policy is based on. For multiple policies, you should apply them from the most to least specific. The options are: Option Description Everyone Includes all email users (i.e. internal and external). This option is only available in the "Emails From" section. Internal Address Includes only internal organization addresses. External Address Includes only external organization addresses. This option is only available in the "Emails From" section. Email Domain Enables you to specify a domain name to which this policy is applied. The domain name is entered in the Specifically field. Address Groups Enables you to specify a directory or local group. If this option is selected, click on the Lookup button to select a group from the Profile Group field. Once a group has been selected, you can click on the Show Location field to display the group's path. Address Attributes Enables you to specify a predefined Attribute. The attribute is selected from the Where Attribute drop down list. Once the Attribute is specified, an attribute value must be entered in the Is Equal To field. This can only be used if attributes have been configured for user accounts. Individual Email Address Enables you to specify an SMTP address. The email address is entered in the Specifically field.
- Complete the Validity section as required:
Field / Option Description Enable / Disable Use this to enable (default) or disable a policy. If a date range has been specified, the policy will automatically be disabled when the end of the configured date range is reached. Set Policy as Perpetual If the policy's date range has no end date, this field displays "Always On" meaning that the policy never expires. Date Range Use this field to specify a start and / or end date for the policy. If the Eternal option are selected, no date is required. Policy Override This overrides the default order that policies are applied. If there are multiple applicable policies, this policy is applied first unless more specific policies of the same type are configured with an override. Bi-Directional If selected the policy is applied when the policy's recipient is the sender, and the sender is the recipient. Source IP Ranges (n.n.n.n/x) Enter any required Source IP Ranges for the policy. These only apply if the source IP address used to transmit the message data, falls inside or matches the range(s) configured. IP ranges should be entered in CIDR notation.
- Click on the Save and Exit button.