osquery-defense-kit/detection/privesc/unexpected-elevated-childre...

144 lines
4.4 KiB
SQL

-- Find processes that run with a lower effective UID than their parent (event-based)
--
--
-- references:
-- * https://attack.mitre.org/techniques/T1548/001/ (Setuid and Setgid)
-- * https://cybersecurity.att.com/blogs/labs-research/shikitega-new-stealthy-malware-targeting-linux
--
-- related:
-- * unexpected-privilege-escalation.sql
--
-- tags: events process escalation
-- platform: linux
-- interval: 600
SELECT
file.mode AS p0_binary_mode,
-- Child
pe.path AS p0_path,
pe.time AS p0_time,
REGEX_MATCH (pe.path, '.*/(.*)', 1) AS p0_name,
TRIM(pe.cmdline) AS p0_cmd,
pe.cwd AS p0_cwd,
pe.uid AS p0_uid,
pe.euid AS p0_euid,
pe.pid AS p0_pid,
p.cgroup_path AS p0_cgroup,
-- Parent
pe.parent AS p1_pid,
p1.cgroup_path AS p1_cgroup,
TRIM(COALESCE(p1.cmdline, pe1.cmdline)) AS p1_cmd,
COALESCE(p1.path, pe1.path) AS p1_path,
COALESCE(p1.euid, pe1.euid) AS p1_euid,
COALESCE(p_hash1.sha256, pe_hash1.sha256) AS p1_hash,
REGEX_MATCH (COALESCE(p1.path, pe1.path), '.*/(.*)', 1) AS p1_name,
-- Grandparent
COALESCE(p1.parent, pe1.parent) AS p2_pid,
COALESCE(p1_p2.cgroup_path, pe1_p2.cgroup_path) AS p2_cgroup,
TRIM(
COALESCE(p1_p2.cmdline, pe1_p2.cmdline, pe1_pe2.cmdline)
) AS p2_cmd,
COALESCE(p1_p2.path, pe1_p2.path, pe1_pe2.path) AS p2_path,
COALESCE(
p1_p2_hash.path,
pe1_p2_hash.path,
pe1_pe2_hash.path
) AS p2_hash,
REGEX_MATCH (
COALESCE(p1_p2.path, pe1_p2.path, pe1_pe2.path),
'.*/(.*)',
1
) AS p2_name
FROM
process_events pe
LEFT JOIN file ON pe.path = file.path
LEFT JOIN processes p ON pe.pid = pe.pid -- Parents (via two paths)
LEFT JOIN processes p1 ON pe.parent = p1.pid
LEFT JOIN hash p_hash1 ON p1.path = p_hash1.path
LEFT JOIN process_events pe1 ON pe.parent = pe1.pid
AND pe1.cmdline != ''
LEFT JOIN hash pe_hash1 ON pe1.path = pe_hash1.path -- Grandparents (via 3 paths)
LEFT JOIN processes p1_p2 ON p1.parent = p1_p2.pid -- Current grandparent via parent processes
LEFT JOIN processes pe1_p2 ON pe1.parent = pe1_p2.pid -- Current grandparent via parent events
LEFT JOIN process_events pe1_pe2 ON pe1.parent = pe1_p2.pid
AND pe1_pe2.cmdline != '' -- Past grandparent via parent events
LEFT JOIN hash p1_p2_hash ON p1_p2.path = p1_p2_hash.path
LEFT JOIN hash pe1_p2_hash ON pe1_p2.path = pe1_p2_hash.path
LEFT JOIN hash pe1_pe2_hash ON pe1_pe2.path = pe1_pe2_hash.path
WHERE
pe.pid IN (
SELECT
pid
FROM
process_events
WHERE
time > (strftime('%s', 'now') -600)
AND syscall = "execve"
AND euid < 500
AND (
uid = 0
OR euid < uid
)
)
AND pe.time > (strftime('%s', 'now') -600)
AND pe.syscall = "execve"
AND pe.euid < 500
AND (
pe.euid < pe.uid
OR pe.euid < p1_euid
OR pe.euid < pe1.euid
)
AND pe.path NOT IN (
'/bin/ps',
'/usr/bin/doas',
'/usr/bin/fusermount',
'/usr/bin/fusermount3',
'/usr/bin/login',
'/usr/bin/i3lock',
'/usr/bin/sudo',
'/usr/bin/nvidia-modprobe',
'/usr/bin/unix_chkpwd',
'/usr/bin/gpgsm',
'/usr/bin/gpgconf',
'/usr/bin/gpg',
'/usr/bin/top',
'/usr/lib/snapd/snap-confine',
'/usr/lib/snapd/snap-update-ns',
'/opt/1Password/1Password-KeyringHelper',
'/usr/lib/systemd/systemd',
'/usr/lib/Xorg.wrap',
'/usr/lib/xorg/Xorg.wrap'
)
AND pe.path NOT LIKE '/nix/store/%/bin/sudo'
AND pe.path NOT LIKE '/nix/store/%/bin/dhcpcd'
AND pe.path NOT LIKE '/snap/snapd/%/usr/lib/snapd/snap-confine'
AND pe.path NOT LIKE '/snap/snapd/%/usr/lib/snapd/snap-update-ns'
AND NOT p1_cmd IN (
'/usr/lib/systemd/systemd --user',
'/bin/sh -c /usr/bin/pkexec /usr/share/apport/apport-gtk'
)
AND NOT p0_cmd = '/usr/bin/pkexec /usr/lib/update-notifier/package-system-locked'
AND NOT (
p0_name = 'polkit-agent-helper-1'
AND p1_path IN (
'/usr/bin/gnome-shell',
'/usr/lib/gvfsd',
'/usr/lib/polkit-gnome/polkit-gnome-authentication-agent-1'
)
)
AND NOT (
p0_name = 'fusermount3'
AND p1_path = '/usr/lib/xdg-document-portal'
)
AND NOT (
p0_name IN ('dash', 'pkexec')
AND p1_path = '/usr/bin/update-notifier'
) -- A bizarro persistent false-positive from an Arch linux host
AND NOT (
p.cgroup_path = "/init.scope"
AND p1.cgroup_path != "/init.scope"
)
AND NOT p.cgroup_path LIKE '/system.slice/docker-%'
AND NOT p1.cgroup_path LIKE '/system.slice/docker-%'
GROUP BY
pe.pid