68 lines
2.2 KiB
SQL
68 lines
2.2 KiB
SQL
-- Catch DNS traffic going to machines other than the host-configured DNS server
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-- NOTE: This only supports IPv4 traffic due to an osquery bug with "dns_resolvers"
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-- The non-event version is unexpected-dns-traffic.sql
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SELECT
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protocol,
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s.remote_port,
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s.remote_address,
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p.name,
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p.path,
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p.cmdline AS child_cmd,
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p.cwd,
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s.pid,
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p.parent AS parent_pid,
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pp.cmdline AS parent_cmd,
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hash.sha256,
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CONCAT (p.name, ",", remote_address, ",", remote_port) AS exception_key
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FROM
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socket_events s
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LEFT JOIN processes p ON s.pid = p.pid
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LEFT JOIN processes pp ON p.parent = pp.pid
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LEFT JOIN hash ON p.path = hash.path
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WHERE
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s.time > (strftime("%s", "now") -120)
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AND remote_port IN (53, 5353)
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AND remote_address NOT LIKE "%:%"
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AND s.remote_address NOT LIKE "172.1%"
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AND s.remote_address NOT LIKE "172.2%"
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AND s.remote_address NOT LIKE "172.30.%"
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AND s.remote_address NOT LIKE "172.31.%"
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AND s.remote_address NOT LIKE "10.%"
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AND s.remote_address NOT LIKE "192.168.%"
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AND s.remote_address NOT LIKE "127.%"
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AND remote_address NOT IN (
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SELECT DISTINCT
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address
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FROM
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dns_resolvers
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WHERE
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type = "nameserver"
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and address != ""
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)
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-- systemd-resolve sometimes shows up this way
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-- If we could narrow this down using "sys_resolvers" I would, but it is misuse of GROUP_CONCAT
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AND NOT (
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s.pid = -1
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AND s.remote_port = 53
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and p.parent = ""
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)
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-- Some applications hard-code a safe DNS resolver, or allow the user to configure one
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AND s.remote_address NOT IN (
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"1.1.1.1", -- Cloudflare
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"8.8.8.8", -- Google
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"8.8.4.4", -- Google (backup)
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"208.67.222.222", -- OpenDNS
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"75.75.75.75" -- Comcast
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)
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-- Exceptions that specifically talk to one server
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AND exception_key NOT IN ("nessusd,50.16.123.71,53", "coredns,0.0.0.0,53")
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-- Local DNS servers and custom clients go here
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AND p.path NOT IN ("/usr/lib/systemd/systemd-resolved")
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AND p.path NOT LIKE "/Applications/Google Chrome.app/Contents/Frameworks/Google Chrome Framework.framework/Versions/%/Helpers/Google Chrome Helper.app/Contents/MacOS/Google Chrome Helper"
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-- Workaround for the GROUP_CONCAT subselect adding a blank ent
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GROUP BY
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s.remote_address,
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s.remote_port
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HAVING
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remote_address != ""
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