Snort 2.9.4.1 pkg v.2.5.8

fragged

~~I've recently changed from subscriber to paid Snort rules and have disabled the community rules download from update tab, but the rules tab of my interface shows this error:~~


The following input errors were detected:

    GPLv2_community.rules seems to be missing!!! Please verify rules files have been downloaded, then go to the Categories tab and save the rule set again.

~~The drop down list still shows the community rules, but it's obviously empty. Shouldn't the category have been removed when I no longer have the community rules downloaded at all?~~

Editing rules category tab and restarting Snort cleared the empty community rules selection from the rules tab and the error is no more.

bmeeks

@shinzo:

I am noticing that if i disable a few rules in current events, and then click on apply. It Disables the interface but the pid is still running. I then click start on the interface and it just makes a new one pid on top of the old one.

I just tested this scenario and could not reproduce the issue. When you are looking at the icons on the Snort Interfaces tab, remember that starting with this new 2.5.8 package they were swapped so that the green arrow means "Snort is running" and the red X means "Snort is stopped" on the interface. The tooltip text was updated to reflect this. If you hover over the icon for a few seconds the tooltip will appear and show the current state of Snort.

When you say "disabled", are you talking about the text displayed next to the icon? If so, wait several seconds on the page and then hit the refresh button for your browser. See if that changes the display.
Bill

shinzo

Yeah i am aware of the color change. When i say disabled, i mean that in the snort interface, it goes to red. I am not sure if the interface restarts itself after i click apply in the wan rules tab. I will retry what i was doing to see if i can reproduce the issue.

bmeeks

@shinzo:

Yeah i am aware of the color change. When i say disabled, i mean that in the snort interface, it goes to red. I am not sure if the interface restarts itself after i click apply in the wan rules tab. I will retry what i was doing to see if i can reproduce the issue.

No, it should not restart by itself. The APPLY button on the Rules tab simply rebuilds the enforcing rules file and rewrites the snort.conf file. I monitored the active processes during my test and never saw but one running Snort process.

That rule set is a bit large, and it takes several seconds for the process to complete. This can be even longer on a less capable piece of hardware. Make sure you wait until the browser "activity indicator" stops spinning. IE has a spinning icon in the Address Bar, and Firefox also has some kind of status icon but I forget what it is at the moment. Make sure any spinning status indicators or hourglass goes away before you navigate away from the Rules tab.

Bill

shinzo

@bmeeks:

@shinzo:

Yeah i am aware of the color change. When i say disabled, i mean that in the snort interface, it goes to red. I am not sure if the interface restarts itself after i click apply in the wan rules tab. I will retry what i was doing to see if i can reproduce the issue.

No, it should not restart by itself. The APPLY button on the Rules tab simply rebuilds the enforcing rules file and rewrites the snort.conf file. I monitored the active processes during my test and never saw but one running Snort process.

That rule set is a bit large, and it takes several seconds for the process to complete. This can be even longer on a less capable piece of hardware. Make sure you wait until the browser "activity indicator" stops spinning. IE has a spinning icon in the Address Bar, and Firefox also has some kind of status icon but I forget what it is at the moment. Make sure any spinning status indicators or hourglass goes away before you navigate away from the Rules tab.

Bill

I went back and couldn't reproduce it. I think what was happening was when i was trying out the Snort Community and vrt rules yesterday , some where along the line snort didn't restart properly. Since there seemed to be two instances of snort running. when ever i hit apply after removing some of the current_events rules. I would jump over and notice that in the interface window, it was red so i would click to start it again and would spawn another pid.

I will continue messing with it and let you know if anything happens, I also wanted to ask something about what i read the other day.
Would it be better to have 1 wan interface with the wan ip and lan address or separate them and have 1 wan and then 1 lan? and thanks again

bmeeks

@shinzo:

I also wanted to ask something about what i read the other day.
Would it be better to have 1 wan interface with the wan ip and lan address or separate them and have 1 wan and then 1 lan? and thanks again

If we are talking about a typical home network with NAT, then it depends on whether or not you want to identify specific hosts on the LAN side. Here's what I mean. When you have NAT, then Snort sees everything on the WAN in terms of your WAN IP address and then whatever Internet hosts are being contacted. Snort does not see the internal LAN private IPs. It will still block offending traffic by blocking the SRC (assuming you have that configured for the WAN interface). But the logs will show everything in the local network as having the WAN IP address.

So if you want to see your LAN private IP addresses in the logs and thus be able to identify which specific LAN host might contain the latest nasty online banking Trojan, then you would run an instance of Snort on your LAN interface. This is what I do. I have Snort on the WAN configured with some basic ET-CIARMY and ET-RBN rules, then run the Snort VRT IPS-Balanced policy on my LAN interface. I configured my LAN interface to block BOTH (source and destination). The auto-whitelisting feature that adds the LAN to the whitelist means my LAN IPs never get blocked, but if any LAN IP tries to "phone home" to a BOT C-n-C server on the web, then the DST would get blocked because of the BOTH setting. So I am protected either way (whether my LAN host initiates the conversation or the far-end host does). Plus, my logs now show me the internal LAN private IP of the infected or potentially infected host.

P.S. – while you can do it, it would be sort of pointless and a waste of resources to run a duplicate set of rules on both the WAN and LAN interfaces in a scenario like I described. I prefer the setup where known bad hosts are blocked right away at the perimeter (the WAN). I get this from those ET-CIARMY and RBN rules. Then my LAN side interface is the next layer of protection and contains the richer rule set.

Bill

shinzo

@bmeeks:

@shinzo:

I also wanted to ask something about what i read the other day.
Would it be better to have 1 wan interface with the wan ip and lan address or separate them and have 1 wan and then 1 lan? and thanks again

If we are talking about a typical home network with NAT, then it depends on whether or not you want to identify specific hosts on the LAN side. Here's what I mean. When you have NAT, then Snort sees everything on the WAN in terms of your WAN IP address and then whatever Internet hosts are being contacted. Snort does not see the internal LAN private IPs. It will still block offending traffic by blocking the SRC (assuming you have that configured for the WAN interface). But the logs will show everything in the local network as having the WAN IP address.

So if you want to see your LAN private IP addresses in the logs and thus be able to identify which specific LAN host might contain the latest nasty online banking Trojan, then you would run an instance of Snort on your LAN interface. This is what I do. I have Snort on the WAN configured with some basic ET-CIARMY and ET-RBN rules, then run the Snort VRT IPS-Balanced policy on my LAN interface. I configured my LAN interface to block BOTH (source and destination). The auto-whitelisting feature that adds the LAN to the whitelist means my LAN IPs never get blocked, but if any LAN IP tries to "phone home" to a BOT C-n-C server on the web, then the DST would get blocked because of the BOTH setting. So I am protected either way (whether my LAN host initiates the conversation or the far-end host does). Plus, my logs now show me the internal LAN private IP of the infected or potentially infected host.

P.S. – while you can do it, it would be sort of pointless and a waste of resources to run a duplicate set of rules on both the WAN and LAN interfaces in a scenario like I described. I prefer the setup where known bad hosts are blocked right away at the perimeter (the WAN). I get this from those ET-CIARMY and RBN rules. Then my LAN side interface is the next layer of protection and contains the richer rule set.

Bill

i haven't even considered a setup like that, thanks for your input

Supermule

Hi Bill.

Can you test a client IP header rule that triggers in this scenario?

The way NAT reflection works is that the packets go to the firewall, and are then sent from the firewall to the NAT target, changed to appear as if they came from the firewall, so that replies go back through the firewall.

There is no security issue there, unless you count the loss of the client IP from the perspective of the NAT target/server. The server sees the firewall itself as the "client", not the actual IP of the client.

bmeeks

@Supermule:

Hi Bill.

Can you test a client IP header rule that triggers in this scenario?

The way NAT reflection works is that the packets go to the firewall, and are then sent from the firewall to the NAT target, changed to appear as if they came from the firewall, so that replies go back through the firewall.

There is no security issue there, unless you count the loss of the client IP from the perspective of the NAT target/server. The server sees the firewall itself as the "client", not the actual IP of the client.

Supermule:

I'm not sure I understand what you are asking me to do. If in reference to my previous post, the point of that post to Shinzo was simply to show a mechanism to see the pre-NAT LAN IP addresses in the Snort logs. If you run Snort on just the WAN (and you are using NAT), then Snort logs all "local" traffic as originating from the WAN IP. Here is an example. Suppose host 192.168.0.1 on the LAN communicates with a BOT C-n-C server somewhere on the web. Snort will see and log that traffic, but what you will see in the ALERT log for the Source IP is your WAN IP and then the Destination IP of the BOT C-n-C server. So while you will know that you have an infected host on your LAN, you won't know from the Snort logs which one it is.

However, with my scheme (Snort on LAN), then you will see in the ALERT log the local pre-NAT LAN IP of the infected host (192.168.0.1 in my example) as well as the Destination IP of the C-n-C server. You can then tell which LAN host is the problem.

Bill

Supermule

I understand :)

AhnHEL

@bmeeks:

P.S. – while you can do it, it would be sort of pointless and a waste of resources to run a duplicate set of rules on both the WAN and LAN interfaces in a scenario like I described. I prefer the setup where known bad hosts are blocked right away at the perimeter (the WAN). I get this from those ET-CIARMY and RBN rules. Then my LAN side interface is the next layer of protection and contains the richer rule set.

Bill

Whats your recommendation then for this setup in regards to duplicate settings on the Preprocessors tab? Are they unnecessarily redundant?

masli

Thanks for the new snort interface.

Ok , my problem is…..

Base on my understanding with snort blocking capabilities

LAN setting - I can block both LAN@internal and External IP with selection of new whitelist setting which i have uncheck the "Add firewall Local Networks to the list (excluding WAN)." option. Block setting "both"

WAN setting - I can block external setting , wth default whitelist setting. Block setting "both"

Both LAN and WAN setting will have different categories selection base on my need and requirement.

For the above setting , I manage to

WAN Setting - block external IP
LAN Setting - block only external IP (supposely to block both internal@LAN ip and external IP)

When I view the whitelist IP with "view list" function , in the new whitelist setting, the local IP still there , sort nothing happened with the uncheck action I have done?

Bug? or I missed something?

4 am here, since yesterday morning, I will need to have some rest first. Really appreciate if any one can advice me the next action.

pareddefuego13

2.1-BETA1 (amd64)
built on Fri May 17 16:45:31 EDT 2013
FreeBSD 8.3-RELEASE-p8
Snort v2.9.4.1 pkg v. 2.5.8

Hello,

Ever since I enabled Snort on my LAN interface, my firewall logs have been flooded with the alerts on the attached screen shot. Is there any way to get rid of these alerts? I've been running snort just on the WAN interface for a few good months now and never had these alerts on the firewall logs before. I started to test Snort on the LAN interface a couple of days ago and noticed my firewall log was full of those alerts. I do have IPv6 disabled on the WAN and LAN interfaces. BTW, thanks for this package bmeeks you’ve done a great job with it.

Capture.PNG_thumb

bmeeks

@AhnHEL:

Whats your recommendation then for this setup in regards to duplicate settings on the Preprocessors tab? Are they unnecessarily redundant?

The Preprocessors are unique to each instance of Snort. When you run Snort on more than one interface, you actually have two completely separate and independent processes running – totally separate running copies of the binary. You may already have known that, so forgive me for repeating it if you did. Not trying to insult anyone's skills, but just making sure we start from the same baseline for my explanation below.

So you could certainly- depending on how you have the rule sets selected- use different Preprocessor settings on the different interfaces. It's just my view that on today's reasonably fast hardware the preprocessor overhead is not that big of a deal. I don't think it's nearly as taxing on CPU and RAM as say having duplicate sets of ALL the rules running on the LAN and WAN interfaces. The rules are where all the CPU and RAM resources get used (of course the HTTP_INSPECT, Frag3 and Stream5 can use some extra RAM depending on how they are configured). But in high traffic situations, different preprocessors settings would certainly be the way to go. You just have to be careful that you don't disable a preprocessor that an enabled rule depends on. Doing so will cause those "FATAL ERROR" messages on startup.

So to sum up my answer to your question, if had 2GB or more of RAM and not a lot of load (say less than 50 Mbits/sec) with a reasonably modern CPU; then I would just run the default preprocessor setup on both interfaces.

Bill

bmeeks

@masli:

Thanks for the new snort interface.

Ok , my problem is…..

Base on my understanding with snort blocking capabilities

LAN setting - I can block both LAN@internal and External IP with selection of new whitelist setting which i have uncheck the "Add firewall Local Networks to the list (excluding WAN)." option. Block setting "both"

WAN setting - I can block external setting , wth default whitelist setting. Block setting "both"

Both LAN and WAN setting will have different categories selection base on my need and requirement.

For the above setting , I manage to

WAN Setting - block external IP
LAN Setting - block only external IP (supposely to block both internal@LAN ip and external IP)

When I view the whitelist IP with "view list" function , in the new whitelist setting, the local IP still there , sort nothing happened with the uncheck action I have done?

Bug? or I missed something?

4 am here, since yesterday morning, I will need to have some rest first. Really appreciate if any one can advice me the next action.

I went back and looked at the code. Currently it is by design that the interface Snort is running on (except when it's the WAN) is always added to HOME_NET and the WHITELIST. Do you really want to block your local LAN IP addresses? If so, why? You can easily lock yourself out of the firewall this way (at least lock out a workstation). It has always been the behavior of Snort to add the interface running Snort to HOME_NET and the WHITELIST. What changed in this last update was instead of whitelisting the entire WAN subnet, only the WAN IP is whitelisted. The checkbox just adds all the other locally attached firewall networks to HOME_NET and the WHITELIST. Formerly these were not added by default.

Bill

bmeeks

@pareddefuego13:

2.1-BETA1 (amd64)
built on Fri May 17 16:45:31 EDT 2013
FreeBSD 8.3-RELEASE-p8
Snort v2.9.4.1 pkg v. 2.5.8

Hello,

Ever since I enabled Snort on my LAN interface, my firewall logs have been flooded with the alerts on the attached screen shot. Is there any way to get rid of these alerts? I've been running snort just on the WAN interface for a few good months now and never had these alerts on the firewall logs before. I started to test Snort on the LAN interface a couple of days ago and noticed my firewall log was full of those alerts. I do have IPv6 disabled on the WAN and LAN interfaces. BTW, thanks for this package bmeeks you’ve done a great job with it.

Traffic on port 1900 to that destination IPv6 address is SSDP (Simple Service Discovery Protocol) traffic. Snort does not, to the best of my knowledge, generate such traffic and has no need for it. I would say this is not related to enabling Snort on the LAN.

Bill

pareddefuego13

thanks Bill for your answer…but its weird, if I disable Snort on the LAN interface, those log entries stop and only return if I enable Snort on the LAN interface again.

AhnHEL

@bmeeks:

So to sum up my answer to your question, if had 2GB or more of RAM and not a lot of load (say less than 50 Mbits/sec) with a reasonably modern CPU; then I would just run the default preprocessor setup on both interfaces.

Thank you Bill for your clear and concise reply. Snort has jumped in leaps and bounds since you started contributing and adding to Ermal's package. ;D

masli

I have no choice with referring to torrent or p2p blocking 2with snort. With current version, without blocking the client who is downloading using torrent software. Not much can be done as the client kept continue downloading the file without failure. I have try it with my notebook , even though snort manage to block some external IP (using both LAN and WAN setting) , my torrent software keep continue downloading as nothing blocking it at all.

I do understand that with the setting I intended to used , my client or some workstation will be accidentally block(if they forgot to shut off their torrent software. But it sort like reminder to the client not to use torrent software in my network. After all with cron , it will only block for 5 min. So the client must make sure their pc is according to my requirement within 5 minute.

Really appreciate if the whitelist issue can be settle.

@bmeeks:

@masli:

Thanks for the new snort interface.

Ok , my problem is…..

Base on my understanding with snort blocking capabilities

LAN setting - I can block both LAN@internal and External IP with selection of new whitelist setting which i have uncheck the "Add firewall Local Networks to the list (excluding WAN)." option. Block setting "both"

WAN setting - I can block external setting , wth default whitelist setting. Block setting "both"

Both LAN and WAN setting will have different categories selection base on my need and requirement.

For the above setting , I manage to

WAN Setting - block external IP
LAN Setting - block only external IP (supposely to block both internal@LAN ip and external IP)

When I view the whitelist IP with "view list" function , in the new whitelist setting, the local IP still there , sort nothing happened with the uncheck action I have done?

Bug? or I missed something?

4 am here, since yesterday morning, I will need to have some rest first. Really appreciate if any one can advice me the next action.

I went back and looked at the code. Currently it is by design that the interface Snort is running on (except when it's the WAN) is always added to HOME_NET and the WHITELIST. Do you really want to block your local LAN IP addresses? If so, why? You can easily lock yourself out of the firewall this way (at least lock out a workstation). It has always been the behavior of Snort to add the interface running Snort to HOME_NET and the WHITELIST. What changed in this last update was instead of whitelisting the entire WAN subnet, only the WAN IP is whitelisted. The checkbox just adds all the other locally attached firewall networks to HOME_NET and the WHITELIST. Formerly these were not added by default.

Bill

bmeeks

@masli:

I have no choice with referring to torrent or p2p blocking 2with snort. With current version, without blocking the client who is downloading using torrent software. Not much can be done as the client kept continue downloading the file without failure. I have try it with my notebook , even though snort manage to block some external IP (using both LAN and WAN setting) , my torrent software keep continue downloading as nothing blocking it at all.

I do understand that with the setting I intended to used , my client or some workstation will be accidentally block(if they forgot to shut off their torrent software. But it sort like reminder to the client not to use torrent software in my network. After all with cron , it will only block for 5 min. So the client must make sure their pc is according to my requirement within 5 minute.

Really appreciate if the whitelist issue can be settle.

I can make the change, but I have to figure out a way to incorporate it so it does not break existing settings for folks who do not want to use it in the same manner. I will put this on the To-Do list for the next release. I will alter the WHITELIST so the Local Networks (including the interface Snort is running on) are not automatically included when the new Checkbox is cleared.

In the meantime, I can show you how to modify the default behavior on your system if you will PM (Private Message) me.

Bill