Application Whitelist Example

Keep in mind that you do not need to capture every application that might be in use on your network in your initial inventory. Instead you should focus on the applications (and general types of applications) that you want to allow. Temporary rules in the best practice rulebase will catch any additional applications that may be in use on your network so that you are not inundated with complaints of broken applications during your transition to application-based policy. The following is an example application whitelist for an enterprise gateway deployment.
Application Type
Best Practice for Securing
SaaS Applications
SaaS application service providers own and manage the software and infrastructure, but you retain full control of the data, including who can create, access, share, and transfer it.
Generate a SaaS applications usage report to check if SaaS applications currently in use have unfavorable hosting characteristics such as past data breaches or lack of proper certifications. Based on business needs and the amount of risk you’re willing to accept, use the information to:
  • Block existing applications with unfavorable hosting characteristics immediately.
  • Create granular policies that block applications with unfavorable hosting characteristics to prevent future violations.
  • Identify network traffic trends of the top applications that have unfavorable hosting characteristics so you can adjust policy accordingly.
Sanctioned Applications
These are the applications that your IT department administers specifically for business use within your organization or to provide infrastructure for your network and applications. For example, in an internet gateway deployment these applications fall into the following categories:
  • Infrastructure Applications
    —These are the applications that you must allow to enable networking and security, such as ping, NTP, SMTP, and DNS.
  • IT Sanctioned Applications
    —These are the applications that you provision and administer for your users. These fall into two categories:
    • IT Sanctioned On-Premise Applications
      —These are the applications you install and host in your data center for business use. With IT sanctioned on-premise applications, the application infrastructure and the data reside on enterprise-owned equipment. Examples include Microsoft Exchange and active sync, as well as authentication tools such as Kerberos and LDAP.
    • IT Sanctioned SaaS Applications
      —These are SaaS applications that your IT department has sanctioned for business purposes, for example, Salesforce, Box, and GitHub.
  • Administrative Applications
    —These are applications that only a specific group of administrative users should have access to in order to administer applications and support users (for example, remote desktop applications).
Tag all sanctioned applications with the predefined
Sanctioned
tag. Panorama and firewalls consider applications without the Sanctioned tag as unsanctioned applications.
General Types of Applications
Besides the applications you officially sanction and deploy, you will also want to allow your users to safely use other types of applications:
  • General Business Applications
    —For example, allow access to software updates, and web services, such as WebEx, Adobe online services, and Evernote.
  • Personal Applications
    —For example, you may want to allow your users to browse the web or safely use web-based mail, instant messaging, or social networking applications, including consumer versions of some SaaS applications.
Begin with wide application filters to gain an understanding of what applications are in use on your network. You can then decide how much risk you are willing to assume and begin to pare down the application whitelist. For example, suppose multiple messaging applications are in use, each with the inherent risk of data leakage, transfer of malware-infected files, etc. The best approach is to officially sanction a single messaging application and then begin to phase out the others by slowly transitioning from an allow policy to an alert policy, and finally, after giving users ample warning, a block policy for all messaging applications except the one you choose to sanction. In this case, you might also choose to enable a small group of users to continue using an additional messaging application as needed to perform job functions with partners.
Custom Applications Specific to Your Environment
If you have proprietary applications on your network or applications that you run on non-standard ports, it is a best practice to create custom applications for each of them. This way you can allow the application as a sanctioned application (and apply the predefined Sanctioned tag) and lock it down to its default port. Otherwise you would either have to open up additional ports (for applications running on non-standard ports), or allow unknown traffic (for proprietary applications), neither of which are recommended in a best practice Security policy.
If you have existing Application Override policies that you created solely to define custom session timeouts for a set a of ports, convert the existing Application Override policies to application-based policies by configuring service-based session timeouts to maintain the custom timeout for each application and then migrating the rule the an application-based rule. Application Override policies are port-based. When you use Application Override policies to maintain custom session timeouts for a set of ports, you lose application visibility into those flows, so you neither know nor control which applications use the ports. Service-based session timeouts achieve custom timeouts while also maintaining application visibility.

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