mirror of
https://github.com/chainguard-dev/osquery-defense-kit
synced 2024-12-13 09:34:34 +00:00
99 lines
2.9 KiB
SQL
99 lines
2.9 KiB
SQL
-- Catch DNS traffic going to machines other than the host-configured DNS server (state-based)
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--
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-- references:
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-- * https://attack.mitre.org/techniques/T1071/004/ (C2: Application Layer Protocol: DNS)
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--
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-- tags: ephemeral state net
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--
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-- NOTE: This only supports IPv4 traffic due to an osquery bug with 'dns_resolvers'
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SELECT
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s.family,
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protocol,
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s.local_port,
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s.remote_port,
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s.local_address,
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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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GROUP_CONCAT(
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(
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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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','
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) AS sys_resolvers,
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CONCAT (p.name, ',', remote_address, ',', remote_port) AS exception_key
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FROM
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process_open_sockets 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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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 s.protocol = 17
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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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'1.1.1.2', -- 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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'68.105.28.13' -- Cox
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)
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-- Other exceptions
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AND exception_key NOT IN (
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'coredns,0.0.0.0,53',
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'nessusd,50.16.123.71,53',
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'syncthing,46.162.192.181,53'
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)
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-- Local DNS servers and custom clients go here
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AND p.path NOT IN (
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'/usr/lib/systemd/systemd-resolved',
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'/Applications/Slack.app/Contents/Frameworks/Slack Helper.app/Contents/MacOS/Slack Helper',
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'/Applications/Spotify.app/Contents/Frameworks/Spotify Helper.app/Contents/MacOS/Spotify Helper'
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)
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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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-- 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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