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

51 lines
1.5 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
p.pid,
p.name,
key,
value,
LENGTH(value) AS value_len,
p.path,
p.cmdline,
p.parent AS parent_pid,
pp.cmdline AS parent_cmd
-- Querying processes first and filtering by time gives a massive 20X speed improvement
-- over querying process_envs first and JOIN'ing against processes
FROM
processes p
JOIN process_envs pe ON p.pid = pe.pid
LEFT JOIN file f ON p.path = f.path
LEFT JOIN processes pp ON p.parent = pp.pid
WHERE -- This time should match the interval
p.start_time > (strftime('%s', 'now') - 300)
AND (
key = 'HISTFILE'
AND NOT VALUE LIKE '/home/%/.%_history'
)
OR (
key = 'LD_PRELOAD'
AND NOT p.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 ':/snap/%'
AND NOT pe.value LIKE '/app/bin/%'
AND NOT pe.value LIKE 'libmozsandbox.so%'
)
-- setuid
OR (
LENGTH(value) > 1024
AND key != 'LS_COLORS'
AND f.mode IS NOT NULL
AND f.mode NOT LIKE '0%'
)