[Oisf-users] Discrepancies in Snort and Suricata alerts

[Albert E Whale]

Hi Fatema,

I’m curious, are running Suricata in IDS or IPS mode?

I am experiencing significant issues with IPS on a small home office environment.

Sent from my iPhone

> On Sep 24, 2018, at 1:26 PM, fatema bannatwala <fatema.bannatwala at gmail.com> wrote:
> 
> Hi All,
> 
> I am working on getting Suricata up and running with same rulesets as we have for snort.
> Hence running Suricata with both VRT open source free ruleset from Cisco as well as with ET-PRO rule sets from Proofpoint for suricatav4.0.4.
> 
> When I start Suricata it gives some errors for around 200 VRT rules concerning Invalid_Signature/Unknown_Keyword, which make sense as they are not designed to be run with Suricata. But Suricata starts up correctly and works fine inspite of those rule errors.
> 
> My concern is, the number of unique alerts that get triggered in Snort are more than the unique alerts triggered in Suricata, even though both are getting same traffic flow. The difference is huge, i.e. 241 unique Snort alerts compared to only 94 unique alerts in Suricata.
> 
> When did an analysis, the difference is between ETPRO alerts as well as VRT alerts that are triggered in both. And confirmed that the sids that are getting triggered in snort are also enabled in suricata, but still no suricata alerts for those sids.
> 
> Hence, my question is why there is this discrepancy in the alerts that get triggered in snort and not in suricata even when they both are seeing the same traffic and have same sids enabled?
> 
> P.S My initial thought was, either it's because of capture loss in suricata (which is <0.1%), or maybe because of some of those incompatible VRT alerts that are enabled in Suricata, and it is not able to work correctly because of those.
> 
> Has anyone tried this kind on config before?
> 
> Thanks,
> Fatema.
> 
> 
> _______________________________________________
> Suricata IDS Users mailing list: oisf-users at openinfosecfoundation.org
> Site: http://suricata-ids.org | Support: http://suricata-ids.org/support/
> List: https://lists.openinfosecfoundation.org/mailman/listinfo/oisf-users
> 
> Conference: https://suricon.net
> Trainings: https://suricata-ids.org/training/