topic Suspicious TLS Evasion Suggestion in Advanced Threat Prevention Discussions

Suspicious TLS Evasion Suggestion

Mr_Kaplan — Fri, 17 Jan 2020 15:31:54 GMT

In our environment, we use another product for web traffic decryption/inspection. Since that product acts as a proxy and all web traffic gets forwarded to those configured proxy IP addresses, this traffic is getting flagged by our firewalls as suspicious TLS evasion, which is creating a lot of noise. What would be the best solution to this problem? I've seen articles recommending setting the Palo Alto firewalls as DNS proxies, etc., but I'm not sure that's what we want to do and I'm not sure if this would conflict with our web proxies. Should I set exemptions for our web proxy IP addresses in the Anti-Spyware profiles so that it doesn't flag packets destined for them?

Re: Suspicious TLS Evasion Suggestion

SutareMayur — Tue, 18 Feb 2020 05:35:07 GMT

@Mr_KaplanDNS proxy will not fulfill your use case. When Palo alto act as DNS proxy, A Palo Alto Firewall becomes intermediate to clients and Servers to resolve domain name queries. You can give exception to your proxy IPs to avoid alerts.

Hope it helps!

Mayur

Re: Suspicious TLS Evasion Suggestion

hisingh — Thu, 20 Feb 2020 03:20:15 GMT

Hello,

DNS proxy will not conflict with our web proxies. A Palo Alto Networks firewall intermediate to clients and servers can act as a DNS proxy to resolve domain name queries. Basically, the firewall can resolve corporate domains based on a corporate DNS server hostname-to-IP-address mappings, and resolve other domains using a public or ISP DNS server. That way the if the final domain's IP is been different due to load-balanced, Firewall has the correct information and it will not trigger the "Suspicious TLS Evasion Suggestion"

Best

Himani