App Control Advance: Exclusion Logic

10/14/2021 155 9139

DESCRIPTION:

Many a times, App control application/signature exclusion does not work as configured.

The logic for exclusion which firewall understands is if category is blocked completely , then it will skip the checking for exclusion/inclusion list of its corresponding applications. Similarly, if application is blocked completely, then it will skip the checking for the exclusion/inclusion list of its corresponding signatures.

 EXAMPLE: Lets take an example of 'Multimedia' category which has been blocked completely through application control advanced but we need to access YouTube website.

If we directly go to the application YouTube and configure it with an exclusion list, it will fail to execute the exclusion list because at the category level it has been blocked and hence firewall will not check the exclusion list of individual applications.

• SonicOS 7.X
  
  

• SonicOS 6.5
  
  
  

• Due to this, YouTube will still be blocked for all devices as the exclusion logic is not applied.
  

RESOLUTION:

Resolution for SonicOS 7.X

This release includes significant user interface changes and many new features that are different from the SonicOS 6.5 and earlier firmware. The below resolution is for customers using SonicOS 7.X firmware.

A reverse logic should be implemented to achieve these kind of requirements. Lets take the same example where multimedia category is still blocked and YouTube needs to be allowed.

• Instead of configuring the exclusion list, we will configure a reverse logic where we will configure the inclusion list as shown below. Here, firewall will check the exclusion/inclusion list as now the block has been disabled which is different than its parent category level. 
  
  
• Now the "testpc" device should be able to access YouTube.
  
  
  NOTE: Same logic can be applied for signature level as well if we have specific signature which needs to be excluded but its parent application needs to be blocked.

Please refer to the following information if internal DNS servers are being used in the network.

• Even after following the above steps mentioned in this article, if the users are unable to access the allowed application then the issue might be due to using internal DNS servers and these DNS servers may not have been added to the "Included IP Address Range" or "Included Users/Groups" field in the above scenario. The following points explains the reason behind adding the DNS servers to the list and various methods on how to allow DNS servers traffic from App Control.
• Many applications have DNS queries as one of the signature. When internal DNS servers are used, all DNS queries from every user device in the network goes through these internal DNS servers. When DNS servers are not added to the allowed list of these applications then even the allowed users will be unable to access the applications as the DNS queries are being blocked.

• If an IP Address Group is being used to allow a group of IP addresses from an application then it would be recommended to add the DNS server IP address also to this Address Group.

• 
  

  If a User Group is being used to allow a group of users from an application. Try one of the following,

  
  

  
  

- If the DNS server also has a user account then this user account can be added to the allowed User Group

- If DNS server User account cannot be added to the User Group then DNS server IP address can be excluded in two ways,

1. Add the DNS servers to the global App Control Exclusion List or else,

2. Instead of using App Control, use App Rules to exclude both User Group and IP Address Object/Group.

• If both User Group and IP address Group is selected to be in the "Included" field of an Application in App control, then the only traffic that will be allowed is the traffic that is matching both IP Address Group AND also User Group. If the traffic matches either IP Address Group OR User Group then the traffic will not be allowed.

Resolution for SonicOS 6.5

This release includes significant user interface changes and many new features that are different from the SonicOS 6.2 and earlier firmware. The below resolution is for customers using SonicOS 6.5 firmware.

A reverse logic should be implemented to achieve these kind of requirements. Lets take the same example where multimedia category is still blocked and YouTube needs to be allowed.

• Instead of configuring the exclusion list, we will configure a reverse logic where we will configure the inclusion list as shown below. Here, firewall will check the exclusion/inclusion list as now the block has been disabled which is different than its parent category level.
  
  
  NOTE: Same logic can be applied for signature level as well if we have specific signature which needs to be excluded but its parent application needs to be blocked.

Please refer to the following information if internal DNS servers are being used in the network.

• Even after following the above steps mentioned in this article, if the users are unable to access the allowed application then the issue might be due to using internal DNS servers and these DNS servers may not have been added to the "Included IP Address Range" or "Included Users/Groups" field in the above scenario. The following points explains the reason behind adding the DNS servers to the list and various methods on how to allow DNS servers traffic from App Control.
• Many applications have DNS queries as one of the signature. When internal DNS servers are used, all DNS queries from every user device in the network goes through these internal DNS servers. When DNS servers are not added to the allowed list of these applications then even the allowed users will be unable to access the applications as the DNS queries are being blocked.

• If an IP Address Group is being used to allow a group of IP addresses from an application then it would be recommended to add the DNS server IP address also to this Address Group.

• 
  

  If a User Group is being used to allow a group of users from an application. Try one of the following,

  
  

  
  

- If the DNS server also has a user account then this user account can be added to the allowed User Group

- If DNS server User account cannot be added to the User Group then DNS server IP address can be excluded in two ways,

1. Add the DNS servers to the global App Control Exclusion List or else,

2. Instead of using App Control, use App Rules to exclude both User Group and IP Address Object/Group.

• If both User Group and IP address Group is selected to be in the "Included" field of an Application in App control, then the only traffic that will be allowed is the traffic that is matching both IP Address Group AND also User Group. If the traffic matches either IP Address Group OR User Group then the traffic will not be allowed.

ISSUE ID:

Jira GEN6-2534