Suricata rule 1:2025146 ET DNS Query for Suspicious Domain



  • Hello,

    lately i am getting alerts of the rule 1:2025146 and my the dns servers that i am using are getting blocked, does anybody know how can i view those dns queries ? I tried to capture dns traffic but i don't have a dedicated pc for monitoring.

    I am trying to understand the alert and see if it is a false positive, any help is appreciated.

    Thank you very much.


  • Galactic Empire

    Does Suricata capture the offending packet?

    Snort does.

    ET DNS Query for Suspicious .gr.com Domain (gr.com in DNS Lookup)

    LOL Suspicious indeed, any random hostname returns 72.34.38.11 :-

    mac-pro:~ andy$ nslookup qjkcvjhads.gr.com
    Server: xxxxxxxxxx
    Address: xxxxxxxxxx#53

    Non-authoritative answer:
    Name: qjkcvjhads.gr.com
    Address: 72.34.38.11

    mac-pro:~ andy$ nslookup kfvovdkjds.gr.com
    Server: xxxxxxxxxx
    Address: xxxxxxxxxx#53

    Non-authoritative answer:
    Name: kfvovdkjds.gr.com
    Address: 72.34.38.11

    mac-pro:~ andy$


  • Galactic Empire

    It could have been a host looking up *gr.com, looks like there was an issue with the rule, try updating your rules :-

    http://docs.emergingthreats.net/bin/view/Main/2025146

    "This alert is generating ~30+ false positives per hour in our IDS because it is hitting on any domain ending in "gr.com" instead of the actual domain of ".gr.com" such as angr.com or pulsemgr.com. Please change to 'content:".gr.com".'"



  • It looks like rule was corrected:

    alert dns $HOME_NET any -> any any (msg:"ET DNS Query for Suspicious .gr.com Domain (gr .com in DNS Lookup)"; dns_query; content:".gr.com"; isdataat:!1,relative; metadata: former_category DNS; reference:url,www.domain.gr.com; classtype:bad-unknown; sid:2025146; rev:3; metadata:created_at 2017_12_12, updated_at 2017_12_18;)
    


  • NogBadTheBad and ecfx thank you for your instant reply.

    The site of Emerging Threats is very useful.