osquery-defense-kit/net/unexpected-dns-traffic-events.sql
2022-09-29 15:42:27 -04:00

80 lines
2.5 KiB
SQL

-- Catch DNS traffic going to machines other than the host-configured DNS server
-- NOTE: This only supports IPv4 traffic due to an osquery bug with "dns_resolvers"
-- The non-event version is unexpected-dns-traffic.sql
SELECT
protocol,
s.remote_port,
s.remote_address,
p.name,
p.path,
p.cmdline AS child_cmd,
p.cwd,
s.pid,
p.parent AS parent_pid,
pp.cmdline AS parent_cmd,
hash.sha256,
CONCAT (p.name, ",", remote_address, ",", remote_port) AS exception_key
FROM
socket_events s
LEFT JOIN processes p ON s.pid = p.pid
LEFT JOIN processes pp ON p.parent = pp.pid
LEFT JOIN hash ON p.path = hash.path
WHERE
s.time > (strftime("%s", "now") -120)
AND remote_port IN (53, 5353)
AND remote_address NOT LIKE "%:%"
AND s.remote_address NOT LIKE "172.1%"
AND s.remote_address NOT LIKE "172.2%"
AND s.remote_address NOT LIKE "172.30.%"
AND s.remote_address NOT LIKE "172.31.%"
AND s.remote_address NOT LIKE "10.%"
AND s.remote_address NOT LIKE "192.168.%"
AND s.remote_address NOT LIKE "127.%"
AND remote_address NOT IN (
SELECT DISTINCT
address
FROM
dns_resolvers
WHERE
type = "nameserver"
and address != ""
)
-- systemd-resolve sometimes shows up this way
-- If we could narrow this down using "sys_resolvers" I would, but it is misuse of GROUP_CONCAT
AND NOT (
s.pid = -1
AND s.remote_port = 53
and p.parent = ""
)
-- Some applications hard-code a safe DNS resolver, or allow the user to configure one
AND s.remote_address NOT IN (
"1.1.1.1", -- Cloudflare
"1.1.1.2", -- Cloudflare
"8.8.8.8", -- Google
"8.8.4.4", -- Google (backup)
"208.67.222.222", -- OpenDNS
"75.75.75.75", -- Comcast
"68.105.28.13" -- Cox
)
-- Exceptions that specifically talk to one server
AND exception_key NOT IN (
"coredns,0.0.0.0,53",
"nessusd,50.16.123.71,53",
"nessusd,52.44.207.89,53",
"syncthing,46.162.192.181,53"
)
-- Local DNS servers and custom clients go here
AND p.path NOT IN (
"/usr/lib/systemd/systemd-resolved",
"/Applications/Slack.app/Contents/Frameworks/Slack Helper.app/Contents/MacOS/Slack Helper",
"/Applications/Spotify.app/Contents/Frameworks/Spotify Helper.app/Contents/MacOS/Spotify Helper"
)
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"
-- Workaround for the GROUP_CONCAT subselect adding a blank ent
GROUP BY
s.remote_address,
s.remote_port
HAVING
remote_address != ""