One of the most prevalent ways that malware is delivered to an endpoint is via drive-by download over an SSL connection. This type of attack is typically used in conjunction with some other form of attack (i.e. spear phishing, watering hole, etc.). A drive-by download is a download that occurs without a user's knowledge when visiting a website. The access method (i.e. browser, application, etc.) is exploited to automate the process so that the user is unable to take action until it is too late. Attackers will register new domains that have yet to be categorized by URL filtering products in attempts to bypass URL categories traditionally categorized as malicious, phishing, etc. Palo Alto Networks firewalls can intercept drive-by downloads because its URL filtering, file blocking, and SSL decryption capabilities are natively-integrated.
PAN-DB URL filtering within Palo Alto Networks firewalls have an unknown category to match newly registered domains by attackers, but more importantly, URL categories (whether pre-defined or custom) can be leveraged as match criteria within a security policy.
The security policy above signifies that any traffic going from domain users on the internal network to any website categorized as unknown on the outside internet will be allowed, but have specific Content-ID profiles applied. In this particular policy, we specify a File Blocking profile called Drive-by.
The File Blocking profile above signifies that any application or file type that is seen will result in a continue action. This means that if a user accesses an unknown URL and a file download or upload is attempted, then a response page will be generated forcing the user to either confirm or deny the download. Other options include alert (log and allow) and block (log and block). This is even when the session is encrypted over SSL. The response page can be customized, of course.
In summary, as the number of devices connected to the internet continue to rise, the more threats will also continue to rise. Its almost impossible to keep up with disparate products, logs, etc. and no correlation. Leveraging a platform with native URL filtering integration allows us to automate outcomes with very little to no manual intervention on our part.
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