new detector: unexpected sysctl calls

detection/execution/unexpected-sysctl-calls.sql

@@ -0,0 +1,68 @@
+-- Unexpected calls to sysctl (event-based)
+--
+-- refs:
+--   * https://attack.mitre.org/techniques/T1497/001/ (Virtualization/Sandbox Evasion: System Checks)
+--
+-- platform: posix
+-- interval: 900
+SELECT
+  pe.path AS child_path,
+  pe.cwd AS child_cwd,
+  REGEX_MATCH (pe.path, '.*/(.*)', 1) AS child_name,
+  TRIM(pe.cmdline) AS child_cmd,
+  pe.pid AS child_pid,
+  p.cgroup_path AS child_cgroup,
+  p.parent AS parent_pid,
+  TRIM(IIF(pp.cmdline != NULL, pp.cmdline, ppe.cmdline)) AS parent_cmd,
+  TRIM(IIF(pp.path != NULL, pp.path, ppe.path)) AS parent_path,
+  IIF(pp.path != NULL, phash.sha256, pehash.sha256) AS parent_hash,
+  REGEX_MATCH (
+    IIF(pp.path != NULL, pp.path, ppe.path),
+    '.*/(.*)',
+    1
+  ) AS parent_name,
+  TRIM(IIF(gp.cmdline != NULL, gp.cmdline, gpe.cmdline)) AS gparent_cmd,
+  TRIM(IIF(gp.path != NULL, gp.path, gpe.path)) AS gparent_path,
+  IIF(gp.path != NULL, gphash.sha256, gpehash.path) AS gparent_hash,
+  REGEX_MATCH (
+    IIF(gp.path != NULL, gp.path, gpe.path),
+    '.*/(.*)',
+    1
+  ) AS gparent_name,
+  IIF(pp.parent != NULL, pp.parent, ppe.parent) AS gparent_pid,
+  CONCAT (
+    MIN(pe.euid, 500),
+    ',',
+    REGEX_MATCH (
+      IIF(pp.path != NULL, pp.path, ppe.path),
+      '.*/(.*)',
+      1
+    ),
+    ',',
+    REGEX_MATCH (
+      IIF(gp.path != NULL, gp.path, gpe.path),
+      '.*/(.*)',
+      1
+    )
+  ) AS exception_key
+FROM
+  process_events pe
+  LEFT JOIN processes p ON pe.pid = p.pid
+  LEFT JOIN processes pp ON pe.parent = pp.pid
+  LEFT JOIN hash phash ON pp.path = phash.path
+  LEFT JOIN process_events ppe ON pe.parent = ppe.pid
+  LEFT JOIN hash pehash ON ppe.path = pehash.path
+  LEFT JOIN processes gp ON gp.pid = pp.parent
+  LEFT JOIN hash gphash ON gp.path = gphash.path
+  LEFT JOIN process_events gpe ON ppe.parent = gpe.pid
+  LEFT JOIN hash gpehash ON gpe.path = gpehash.path
+ WHERE
+  pe.time > (strftime('%s', 'now') -900)
+  AND pe.path IN ('/usr/bin/sysctl', '/sbin/sysctl', '/usr/sbin/sysctl')
+  AND NOT child_cmd IN (
+    'sysctl -n hw.optional.arm64',
+    '/usr/sbin/sysctl -n hw.cputype',
+    'sysctl.proc_translated'
+  )
+GROUP BY
+  pe.pid