osquery-defense-kit/detection/execution/unexpected-env-values-linux...

72 lines
2.2 KiB
SQL

-- Applications setting environment variables to bypass security protections
--
-- Inpsired by BPFdoor and other intrusions
-- https://www.sandflysecurity.com/blog/compromised-linux-cheat-sheet/
--
-- WARNING: This query is known to require a higher than average wall time.
--
-- tags: transient state
-- interval: 300
-- platform: linux
SELECT
pe.key,
pe.value,
LENGTH(pe.value) AS value_len,
-- Child
p0.pid AS p0_pid,
p0.path AS p0_path,
p0.name AS p0_name,
p0.cmdline AS p0_cmd,
p0.cwd AS p0_cwd,
p0.cgroup_path AS p0_cgroup,
p0.euid AS p0_euid,
p0_hash.sha256 AS p0_sha256,
-- Parent
p0.parent AS p1_pid,
p1.path AS p1_path,
p1.name AS p1_name,
p1.cmdline AS p1_cmd,
p1_hash.sha256 AS p1_sha256,
-- Grandparent
p1.parent AS p2_pid,
p2.name AS p2_name,
p2.path AS p2_path,
p2.cmdline AS p2_cmd,
p2_hash.sha256 AS p2_sha256
FROM
-- Querying processes first and filtering by time gives a massive 20X speed improvement
-- over querying process_envs first and JOIN'ing against processes
processes p0
JOIN process_envs pe ON p0.pid = pe.pid
LEFT JOIN file f ON p0.path = f.path
LEFT JOIN hash p0_hash ON p0.path = p0_hash.path
LEFT JOIN processes p1 ON p0.parent = p1.pid
LEFT JOIN hash p1_hash ON p1.path = p1_hash.path
LEFT JOIN processes p2 ON p1.parent = p2.pid
LEFT JOIN hash p2_hash ON p2.path = p2_hash.path
WHERE -- This time should match the interval
p0.start_time > (strftime('%s', 'now') - 300)
AND (
pe.key = 'HISTFILE'
AND NOT pe.value LIKE '/home/%/.%_history'
)
OR (
pe.key = 'LD_PRELOAD'
AND NOT pe.value = ''
AND NOT p0.path LIKE '%/firefox'
AND NOT pe.value IN ('libfakeroot.so', '/usr/local/lib/libmimalloc.so')
AND NOT pe.value LIKE ':/home/%/.local/share/Steam'
AND NOT pe.value LIKE ':/home/%/.var/app/com.valvesoftware.Steam/%'
AND NOT pe.value LIKE ':/home/%/.local/share/Steam/ubuntu%/gameoverlayrenderer.so:/home/%/.local/share/Steam/ubuntu%/gameoverlayrenderer.so'
AND NOT pe.value LIKE ':/snap/%'
AND NOT pe.value LIKE '/app/bin/%'
AND NOT pe.value LIKE 'libmozsandbox.so%'
)
-- setuid
OR (
LENGTH(pe.value) > 1024
AND pe.key != 'LS_COLORS'
AND f.mode IS NOT NULL
AND f.mode NOT LIKE '0%'
)