osquery-defense-kit/detection/evasion/empty_root_environ_linux.sql

91 lines
2.0 KiB
SQL

-- Find programs which spawn root children without propagating environment variables
--
-- references:
-- * https://www.sandflysecurity.com/blog/bpfdoor-an-evasive-linux-backdoor-technical-analysis/
--
-- tags: persistent state daemon process
-- interval: 600
-- platform: linux
SELECT
COUNT(key) AS count,
p.pid,
p.path,
p.name,
p.on_disk,
p.cgroup_path,
hash.sha256,
p.parent,
p.cmdline,
p.cwd,
pp.name AS parent_name,
pp.cmdline AS parent_cmd
-- Processes is 20X faster to scan than process_envs
FROM
processes p
LEFT JOIN hash ON p.path = hash.path
LEFT JOIN process_envs pe ON p.pid = pe.pid
LEFT JOIN processes pp ON p.parent = pp.pid
WHERE
p.euid = 0
-- This time should match the interval
AND p.start_time > (strftime('%s', 'now') - 601)
-- Filter out transient processes that may not have an envs entry by the time we poll for it
AND p.start_time < (strftime('%s', 'now') - 1)
AND p.parent NOT IN (0, 2)
AND NOT p.path IS NULL
AND p.name NOT IN (
'1Password-Keyri',
'abrt-handle-eve',
'applydeltarpm',
'bwrap',
'crond',
'cupsd',
'dhcpcd',
'dnf',
'fprintd',
'gdm-session-wor',
'gdm-x-session',
'gpg-agent',
'modprobe',
'nginx',
'osqueryi',
'realmd',
'dbus-daemon',
'sedispatch',
'ssh',
'sshd',
'sudo',
'systemd',
'systemd-udevd',
'systemd-userdbd',
'systemd-userwor',
'(udev-worker)',
'Xorg',
'zfs',
'zypak-sandbox'
)
AND NOT pp.name IN (
'systemd-userdbd',
'crond',
'systemd',
'systemd-udevd',
'(udev-worker)'
)
AND NOT (
p.name LIKE 'systemd-%'
AND p.parent = 1
)
AND NOT p.cgroup_path IN ('/system.slice/cronie.service')
AND NOT pp.cmdline LIKE 'bwrap %'
AND NOT p.cmdline LIKE '%--type=zygote%'
AND NOT p.cmdline LIKE '%--disable-seccomp-filter-sandbox%'
AND NOT p.cgroup_path LIKE '/system.slice/docker-%'
AND NOT (
p.name = 'sh'
AND p.cgroup_path = '/system.slice/znapzend.service'
)
GROUP BY
p.pid
HAVING
count == 0;