Blocking SSH - Firewall Rule Troubles - SOLVED

acherman · Feb 10, 2015, 6:48 PM

Okay, soooo….

Shaw WAN (WAN1) - 64.141.127.248/29
Telus WAN (WAN2) - 204.191.241.0/29
Public (~DMZ) - 64.141.125.0/24 - advertised on both WANs via BGP

Shaw WAN Rules:

Telus WAN Rules:

Pubic Interface Rules:

All of these are for VoIP devices - companies host POTS lines here and we connect them to VoIP adapters and transport to their remote facilities via our microwave network.

Also, there are no rules in the floating tab.

acherman · Feb 10, 2015, 6:52 PM

@johnpoz:

To be honest anyone that would run a ssh server that allows passwords is asking for trouble, whenever I bring up something that has ssh enabled - first thing I do is enable public key and turn off password auth.

I'm all for more security. What do you mean? Do you use a hardware credential? On these two systems I am the only one that ever uses SSH for access (but limited access).

johnpoz · Feb 10, 2015, 7:57 PM

public key auth - look it up. Takes 2 seconds to implement.

So your routing traffic to this segment behind pfsense. So pfsense has an IP in this network, and it listens on ssh because you enable ssh. So block ssh to that interface IP.

So this segment
Public (~DMZ) - 64.141.125.0/24

Pfsense is what 64.141.125.1 ?? Block traffic to pfsense IP from the public internet - I agree your customers need to do their own firewall if not using your services for that.

acherman · Feb 10, 2015, 8:00 PM

That's what I had done originally - I had rules to block SSH to the interface's real IP and the CARP IP. I will add them again right now.

johnpoz · Feb 10, 2015, 8:14 PM

And you mention you see stuff in the logs for attempted auth.. And what IP are they authing too?

If that is the IP I can validate if ssh is open to the public.

tha_toadman · Feb 10, 2015, 8:18 PM

That's what I had done originally…

I did the same. My rules don't seem to work after I enable the SSH server via the checkbox.

Floating:
block IPv4 TCP/UDP * 22 (SSH) WAN address 22 (SSH) * none

WAN:
block IPv4 TCP/UDP * 22 (SSH) WAN address 22 (SSH) * none

acherman · Feb 10, 2015, 8:32 PM

I just added the rules again and changed the port back to default 22. You can try to SSH to 64.141.125.250, .251 or .254 (CARP).

tha_toadman · Feb 10, 2015, 8:39 PM

I just added the rules again and changed the port back to default 22. You can try to SSH to 64.141.125.250, .251 or .254 (CARP).

They are all open. Sounds like your rules aren't working either.

johnpoz · Feb 10, 2015, 8:44 PM

Source is not going to be 22 source could be ANY, and ssh is not UDP..

And yes that is open!! on the 250, 251 and 254

login as:

Password for admin@router1.morad:

251 shows
steve.morad

tha_toadman · Feb 10, 2015, 8:42 PM

Ah, yep. Good point. I'll make the change and try again.

johnpoz · Feb 10, 2015, 8:46 PM

dude you should not have to put in any rules.. There is a default DENY!! Are you allowing traffic in like the OP?

if your going to block it has to be above your allow rule - post your rules.

If you have an allow for that segment, then above it put in a block to those specific addresses.

acherman · Feb 10, 2015, 8:48 PM

For me, I pretty much never put in a source port. As others have said, they are usually random, so no point. And also, I put them right at the top - since they are handled from the top down, start with the most specific and go from there.

acherman · Feb 10, 2015, 8:51 PM

My DMZ, or Public routed interface rules look like this now…

johnpoz · Feb 10, 2015, 8:55 PM

so anherman - are you rules in place to block it then? Cuz they are still open. 2 all 3 IPs.

So you have a 1:1 nat setup or something? Or your just routing the traffic?

acherman · Feb 10, 2015, 9:07 PM

Yup, those rules are active. No, no 1:1 set up at all. I do have some inbound stuff set up, but specific ports like 21, 80, 443, etc. Although I do have a couple that I have all ports forwarded to 3 customer devices, just because I don't know what ports they use - those are the ones noted in the middle of the WAN rules (noted as BCM access). But those are other IPs. Dumb question, how can I see what IP's they are trying to get authed on? My pfflowd packages aren't working, so I'm not sure how to look.

tha_toadman · Feb 10, 2015, 9:08 PM

For me, I pretty much never put in a source port. As others have said, they are usually random, so no point. And also, I put them right at the top - since they are handled from the top down, start with the most specific and go from there.

Yeah it was towards the end of the day when I put that original rule in. I've since modified it to read as:

block IPv4 TCP * * WAN address 22 (SSH) * none

I've corrected both the Floating and the WAN but I'm still telling you, SSH is open. The default deny isn't working in this case. Once that SSH server is enabled, it's WAN accessible on my box.

My top 3 rules on the WAN tab (apologies on the formatting):

block * Reserved/not assigned by IANA * * * * * * Block bogon networks
block * Private_Networks * * * * none (custom rule)
block IPv4 TCP * * WAN address 22 (SSH) * none Block SSH remote access

I don't have any 1:1 going either.

johnpoz · Feb 10, 2015, 9:15 PM

ok heres another thing - once you create the rules to block. You have to kill the states.. So for example got in.. You need to kill all the states from my IP, or flush them all. Or have to wait til they expire.

acherman · Feb 10, 2015, 9:20 PM

I actually added the rules, and then I turned SSH on and back to 22. Would that have not allowed the states to begin with? Or no?

johnpoz · Feb 10, 2015, 9:22 PM

no that would not have flushed the states in the firewall. That just tells the box to listen or not listen.

acherman · Feb 10, 2015, 9:27 PM

Okay, I just reset all states - that should confuse some people. I will watch the logs now…