osquery-defense-kit/detection/execution/unexpected-xattr-calls-maco...

115 lines
3.8 KiB
SQL

-- Detect unusual calls to xattr, used to remove filesystem attributes
--
-- false positives:
-- * none observed, but they are expected
--
-- interval: 300
-- platform: darwin
-- tags: process events
SELECT
-- Child
pe.path AS p0_path,
REGEX_MATCH (pe.path, '.*/(.*)', 1) AS p0_name,
TRIM(pe.cmdline) AS p0_cmd,
pe.cwd AS p0_cwd,
pe.pid AS p0_pid,
pe.euid AS p0_euid,
s.authority AS p0_authority,
-- Parent
pe.parent AS p1_pid,
TRIM(COALESCE(p1.cmdline, pe1.cmdline)) AS p1_cmd,
COALESCE(p1.path, pe1.path) AS p1_path,
COALESCE(p_hash1.sha256, pe_hash1.sha256) AS p1_hash,
REGEX_MATCH (COALESCE(p1.path, pe1.path), '.*/(.*)', 1) AS p1_name,
pe_sig1.authority AS p1_authority,
-- Grandparent
COALESCE(p1.parent, pe1.parent) AS p2_pid,
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,
COALESCE(
p1_p2_sig.authority,
pe1_p2_sig.authority,
pe1_pe2_sig.authority
) AS p2_authority,
-- Exception key
REGEX_MATCH (pe.path, '.*/(.*)', 1) || ',' || MIN(pe.euid, 500) || ',' || REGEX_MATCH (COALESCE(p1.path, pe1.path), '.*/(.*)', 1) || ',' || REGEX_MATCH (
COALESCE(p1_p2.path, pe1_p2.path, pe1_pe2.path),
'.*/(.*)',
1
) AS exception_key
FROM
process_events pe,
uptime
LEFT JOIN processes p ON pe.pid = p.pid
LEFT JOIN signature s ON pe.path = s.path
-- 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
LEFT JOIN signature pe_sig1 ON pe1.path = pe_sig1.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
LEFT JOIN signature p1_p2_sig ON p1_p2.path = p1_p2_sig.path
LEFT JOIN signature pe1_p2_sig ON pe1_p2.path = pe1_p2_sig.path
LEFT JOIN signature pe1_pe2_sig ON pe1_pe2.path = pe1_pe2_sig.path
WHERE
pe.time > (strftime('%s', 'now') -300)
AND pe.status = 0
AND pe.cmdline != ''
AND pe.cmdline IS NOT NULL
AND pe.status == 0
AND pe.path = '/usr/bin/xattr'
AND p0_cmd NOT LIKE '%xattr -d -r com.apple.quarantine /Applications/%.app'
AND p0_cmd NOT LIKE '%xattr -r -d com.apple.quarantine /Applications/%.app'
AND p0_cmd NOT LIKE '%xattr -d com.apple.quarantine /Applications/%.app'
AND p0_cmd NOT LIKE '%xattr -d com.apple.quarantine /Applications/%.app/%.xpc'
AND NOT (
pe.euid > 500
AND p0_cmd LIKE '%xattr -l %'
)
AND NOT (
pe.euid > 500
AND p0_cmd LIKE '%xattr -p com.apple.quarantine %'
)
AND NOT (
pe.euid > 500
AND p0_cmd LIKE '%xattr -p com.apple.metadata:kMDItemAlternateNames %'
)
AND NOT (
pe.euid > 500
AND p0_cmd LIKE '/usr/bin/xattr -w com.apple.metadata:kMDItemAlternateNames %'
)
AND NOT (
pe.euid > 500
AND p0_cmd LIKE 'xattr -r -d com.apple.quarantine /Users/%/.provisio/bin/%.app'
)
AND NOT (
pe.euid > 500
AND p0_cmd = '/usr/bin/xattr -h'
AND p1_cmd LIKE '%homebrew%'
)
AND p0_cmd NOT LIKE '/usr/bin/xattr -w com.apple.quarantine 0002;%'
AND p0_cmd NOT LIKE '/usr/bin/xattr -w com.apple.quarantine 0181;%'
GROUP BY
pe.pid