Rule to block TOR Application blocks all traffic directed to Internet

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Jacopo_Vigano
L3 Networker

Rule to block TOR Application blocks all traffic directed to Internet

Hello Community,

we have an issue when we try to block TOR application. We do a rule like the image reported below and put it on top of the rulebase:

 Rule_TOR.png

 

But it seems that all Internet traffic is dropped by the rule named "Tor_Blocking".

LOG_TOR.png

 

 We see the Application is "Not-Applicable" on all log files. It seems PaloAlto cannot resolve properly the Applications involved.

 

At the moment we are not using SSL Decryption and we have PANOS 7.0.6 and Application Version 584-3342 on a cluster of PA-5060 appliances.

 

Do you have any idea to resolve this issue?

 

Let me know if you need any other information.

Thanks in advance.

Jacopo

Transporter
L3 Networker

Hi,

 

Not-applicable

Not-applicable means that the Palo Alto device has received data that will be discarded because the port or service that the traffic is coming in on is not allowed, or there is no rule or policy allowing that port or service.
For example, if there was only one rule on the Palo Alto device and that rule allowed the application of web-browsing only on port/service 80, and traffic (web-browsing or any other application) is sent to the Palo Alto device on any other port/service besides 80, then the traffic is discarded or dropped and you'll see sessions with "not-applicable" in the application field.

 

Thnaks

santonic
L5 Sessionator

Destination port in this case is 5671. Do you have any rule which would allow this port?

One explanation would be that it doesn't even start recognising app if this port is not allowed by any rule. Still unusual that it drops it with TOR rule, it should be by some default drop rule at the end.

 

But if this rule blocks http traffic on standard port as well and you have TCP 80 open somewhere (either by service or with web-browsing app) then it's very weird and wrong. 

 

 

Transporter
L3 Networker

Hmm. I didn't read the question properly. I thought it just drops the TOR application. Can you create a rule any any and see if firewall will be able to determine application you are using. generate web or dns request to outside

Jacopo_Vigano
L3 Networker

Hi All,

if I disable the "Tor_blocking" Rule, the application is identify correctly by other rules specified on the rule base and the traffic is accepted and goes to untrust zone.

 

Thanks.

Jacopo

jambulo
L4 Transporter

Im not sure why you're seeing this behavior. We have a similar rule and it works fine. Only difference is we have it set to App-Default for Service. Which should be fine because its "Standard Ports" are TCP/dynamic. You should give that a try.
Jacopo_Vigano
L3 Networker

Hi @jambulo,

I'll ask customer to set application default as "service" and i'll update you.

What version of PANOS are you using?

 

Thanks.

Jacopo.

reaper
L7 Applicator

I'd also recommend changing the source zone from 'any' to 'trust' and instead of setting the negate for rfc-1918, to simply set the destination netwrok to 'any' (as there should not be any rfc-1918 ip addresses upstream and your ISP should drop these anyway)

Tom Piens - PANgurus.com
Like my answer? check out my book! amazon.com/dp/1789956374
Jacopo_Vigano
L3 Networker

Hi All,

customer will try to change the rule in the next few days. I'll update you as soon as possible.

 

Thanks,

Jacopo.

santonic
L5 Sessionator

Can you confirm that you have for example port 80 open somewhere in policy and that TOR rule blocks traffinc on that port anyway?

 

Even if it works with service set to application-default (which is all ports anyway in this case) I still think something is broken here and PA should be notified.

 

 

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