topic Re: Block rogue VPN in General Topics

Block rogue VPN

VincentPresogna — Thu, 23 May 2019 21:44:44 GMT

I am seeing this in my system logs.

IKE phase-1 negotiation is failed. Couldn't find configuration for IKE phase-1 request for peer IP 172.250.246.42[500].

How can I block this? I been a Cisco guy for a longtime and new to Palo Alto. On my old cisco asa I could block an ip at the control plane like this.

access-list cp-outside deny udp host 172.250.246.42 any eq 4500

access-list cp-outside deny udp host 172.250.246.42 any eq 500

access-list cp-outside deny esp host 172.250.246.42 any

What would be the equivelant for Palo Alto?

Re: Block rogue VPN

kiwi — Fri, 24 May 2019 06:31:23 GMT

Hi @VincentPresogna ,

Here's an example on how blocking TOR (for example) :

https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000ClRtCAK

It explains by blocking certain applications :

Create a security policy to block the following applications to the internet:

tor
tor2web
ssh
ssh-tunnel
ike
ipsec-esp
http-proxy

That said, you can also do it similar to the way you describe in your post by blocking service ports 4500 and 500 in the rulebase or in combination with the applications shown above.

Hope this helps.

-Kiwi

Re: Block rogue VPN

BPry — Fri, 24 May 2019 13:01:24 GMT

A couple of ways you could do this. I personally would really look into the 3rd option, but the 1st and 2nd options are quick and easily configured.

1) Specify any IP you wish to block in the policy allowing the traffic and utilize the 'negate-source' option. This will cause the specified source IPs to no-longer match the policy and it will hit the default interzone-default deny policy.

2) Create a Deny 'any' 'any' policy at the top of your rulebase so you can easily block an address from your environment from one static location.

3) Utilize a tool like MineMeld to form a firewall readable External Dynamic List (EDL) and utilize the EDL in the deny policy mentioned above. This has an added benefit of being able to utilize the MineMeld API to programmatically add addresses into the list, which the firewall can pull on a schedule. This means you don't need to actually perform a commit to add an address into your deny policy.

Re: Block rogue VPN

VincentPresogna — Fri, 24 May 2019 20:47:17 GMT

Thank for the inputs. I'll see what I can manage.

Re: Block rogue VPN

VincentPresogna — Fri, 31 May 2019 19:56:12 GMT

Thank's to both of you. I was able to create a simple rule to block/drop that dang ip. I used Kiwi's idea for it. I made a drop rule for that ip with ipsec and ike as the service. BPry, thanks for the MineMeld idea. I was able to get that setup in a day and it's working also.