Snort 2.9.2.3 pkg v. 2.5.1 service fails overnight, unable to restart
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miles267,
you've got quite a few suppressions. In a way it doesn't make too much sense to enable all kind of rules, just to suppress their alerts (unless you are testing snort ;) ). Personally I don't find the sensitive data preproc very useful (so why enable it?).
You should also watch your system log for warnings like
Jul 29 15:32:32 snort[31733]: WARNING: flowbits key 'ET.HTTP.at.SSL' is set but not ever checked.
Jul 29 15:32:32 snort[31733]: WARNING: flowbits key 'ET.bmp_seen' is set but not ever checked.
Jul 29 15:32:32 snort[31733]: WARNING: flowbits key 'ET.MSSQL' is set but not ever checked., where entries like
checked but never set
are worse. My current approach is to specify only the stuff I really need, and then add additional sets to fullfill the state requirements, but not messing with individual rules.
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1. Uninstall (if you have an older version, suggest you not toggle "save settings" to on. In other words, start fresh.
2. Create an alias in pfsense to reflect your old whitelist. You will select this alias in the snort whitelist tab later.
3. Run this command using Diagnostics -> Command Prompt: find /* | grep -i snort | xargs rm -rv (removes old snort references)
4. Install latest. Likely for this version you'll want to make sure that senstive data preprocessor is not selected. I've got all others on.
5. Monitor blocking and prepare to add quite a few exclusions! This is the set I'm using pretty much copy/pasted from the suppression tab:Tried this 3 times, and each night snort fails. I can restart again in the morning with very little effort, but that's clearly not the best solution. I may open a ticket with support about this, as I've spent quite a bit of time dealing with it already.
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miles267,
you've got quite a few suppressions. In a way it doesn't make too much sense to enable all kind of rules, just to suppress their alerts (unless you are testing snort ;) ). Personally I don't find the sensitive data preproc very useful (so why enable it?).
You should also watch your system log for warnings like
Jul 29 15:32:32 snort[31733]: WARNING: flowbits key 'ET.HTTP.at.SSL' is set but not ever checked.
Jul 29 15:32:32 snort[31733]: WARNING: flowbits key 'ET.bmp_seen' is set but not ever checked.
Jul 29 15:32:32 snort[31733]: WARNING: flowbits key 'ET.MSSQL' is set but not ever checked., where entries like
checked but never set
are worse. My current approach is to specify only the stuff I really need, and then add additional sets to fullfill the state requirements, but not messing with individual rules.
Appreciate the insight. Are there a base set of Snort and/or ET rules you'd recommend be enabled for a home network? Currently, I have ICMP and NETBIOS rules enabled on my LAN (not my WAN) and nearly every rule enabled on my WAN. Thanks.
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Appreciate the insight. Are there a base set of Snort and/or ET rules you'd recommend be enabled for a home network? Currently, I have ICMP and NETBIOS rules enabled on my LAN (not my WAN) and nearly every rule enabled on my WAN. Thanks.
While I don't entirely disagree with Fesoj, I spoke with support about enabling snort on the WAN interface if you don't host any external sites. Jim referred to it as the "belt and suspenders" approach, which basically means that there's no point in having Snort on your external interface unless you have some server publicly available, and even then it depends on what kind of server it is (snort can't see inside https, for instance). pfSense blocks everything by default so Snort would just give you a bit of specificity that you don't really need.
For that reason, I keep snort on my LAN interface with all categories enabled (I don't mess with rules much, just categories) and suppress the false positives. There are MANY ways to do this, and mine probably isn't the best but performance is fine and it gives me great insight into my network.
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miles267,
sapere aude!
It all depends on what you want to and where your risks are. That's why you can configure it. What you could do is, set up snort interfaces for the LAN and the WAN side and enable the same rules and attack your system from the LAN side and the WAN side. When your router shows up in alerts as either the destination or source on one side and not on the other, you know on which side the rule makes sense. Unfortunately, this requires some time for testing and learning. As far as NETBIOS goes, I think they are better off on the WAN side (just have a look at the src nets for most of the rules). On the other hand, if your snort box is not an edge router, chances are that you do not need the NETBIOS rules.
Another line of thought is looking at the size of the NETBIOS rule set, which is pretty large. Since many rules are rather MS related, one could doubt that you need them if your desktop boxes are Linux based. Last not least, most of the vulnerabilities have probably been fixed by MS meanwhile.
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I set up the package on 7/27 on PF2.01/Amd64
When the updates processed (last night I think) things broke. I removed the package, reinstalled about 3pm EST and it seems to have fixed things. Just FYI.
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miles267,
snort chokes on the missing sdf declaration. For now, https://github.com/bsdperimeter/pfsense-packages/pull/291/files should solve the problem. I haven't looked at the details why the declaration is missing again, but I guess you've enabled only the ET rules (but I could be wrong).
Fesoj, your code from the github has allowed snort to run on both i386 and amd64 boxes continuously since you originally posted the code. This is with the Sensitive data prepros on with both Snort and ET rules. Checking for updates every six hours, I have not had one error on six different boxes and not all the boxes have the same rules enabled.
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Is it normal to get errors on certain rulesets?
snort[1441]: FATAL ERROR: /usr/local/etc/snort/snort_13690_em0/rules/snort_exploit.rules(362) Unknown rule option: 'ssl_state'.I get similar for botnet-cnc, policy-other, specific-theats. Not always same error.
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I was getting that error on that specific category myself, so you're not alone. Just disable it for now.
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mschiek01,
I could go through the source code and find out under what circumstances the sdf declaration is missing, but if you patch the classification.config file of the ET rules, then the details on how pfSense generates the configuration files for the individual interfaces doesn't matter. With all this patching, the code gets pretty ugly, this is probably the reason why ermal did not patch his sources. My boxes are also running fine without any problems.
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blundar, onhel,
does it matter if you toggle the settings in Snort: Interface Preprocessors and Flow: General Preprocessor Settings: Enable SSL Data? -
I had it disabled when I was getting those errors.
Enabling it fixed snort.botnet-cncstill getting errors on other once, mostly related to dce_iface
Searching around these seem to be related to a conf issue so I'll keep digging.
Thanks!
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I set up the package on 7/27 on PF2.01/Amd64
When the updates processed (last night I think) things broke. I removed the package, reinstalled about 3pm EST and it seems to have fixed things. Just FYI.
This is my exact setup, and I'm still having trouble after a few re-installs. Fails overnight, restart manually is successful.
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I must eat my words! Snort died again last night!
from logs:
20 snort[32228]: Initializing rule chains... Jul 31 12:03:20 snort[32228]: FATAL ERROR: /usr/local/etc/snort/snort_13690_em0/preproc_rules/sensitive-data.rules(1) Unknown ClassType: sdf Jul 31 12:03:20 snort[32228]: FATAL ERROR: /usr/local/etc/snort/snort_13690_em0/preproc_rules/sensitive-data.rules(1) Unknown ClassType: sdf Jul 31 12:03:20 php: : Snort has restarted with your new set of rules... Jul 31 12:03:20 kernel: em0: promiscuous mode disabledUnchecking the "sensitive-data" checkbox for the CC# check, etc. in preprocessors was enough to get snort running again, albeit without some useful checks.
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I must eat my words! Snort died again last night!
Unchecking the "sensitive-data" checkbox for the CC# check, etc. in preprocessors was enough to get snort running again, albeit without some useful checks.
This is my exact same issue. I'm not sure how to find logs for past snort events?
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Services… System logs.
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Services… System logs.
Unfortunately it only displays the last 50 events, which doesn't take me back to the overnight failure.
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blundar,
the sdf problem is known for quite a while and if you search backwards in this thread you'll find a way of handling it.
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you can change the number of lines using the settings tab. I have mine set to 500.
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you can change the number of lines using the settings tab. I have mine set to 500.
Thanks - can't believe I never noticed that. I'll check it again first thing in the AM.
