osquery-defense-kit/fs/unexpected-tmp-executables.sql

-- Find unexpected executables in temp directories
SELECT
  file.path,
  uid,
  gid,
  mode,
  file.mtime,
  file.size,
  hash.sha256,
  magic.data
FROM
  file
  LEFT JOIN hash on file.path = hash.path
  LEFT JOIN magic ON file.path = magic.path
WHERE
  (
    file.path LIKE "/tmp/%%"
    OR file.path LIKE "/var/tmp/%%"
  )
  AND file.type = "regular"
  AND (
    file.mode LIKE "%7%"
    or file.mode LIKE "%5%"
    or file.mode LIKE "%1%"
  )
  AND NOT (
    uid > 500
    AND (
      file.path LIKE "%go-build%"
      OR file.path LIKE "/tmp/checkout/%"
      OR file.path LIKE "/tmp/com.apple.installer%"
      OR file.path LIKE "/tmp/flow/%.npmzS_cacachezStmpzSgit-clone%"
      OR file.path LIKE "/tmp/go-build%/exe/chainctl"
      OR file.path LIKE "/tmp/go.%.sum"
      OR file.path LIKE "/tmp/guile-%/guile-%"
      OR file.path LIKE "/tmp/terraformer/%"
      OR file.path LIKE "/tmp/tmp.%"
      OR file.path LIKE "%/bin/%-gen"
      OR file.path LIKE "%/bin/%"
      OR file.path LIKE "%/CCLBS/%"
      OR file.path LIKE "%/ko/%"
      OR file.path LIKE "%/pdf-tools/%"
      OR file.path LIKE "%/tmp/epdf%"
      OR
      -- These regular expressions can be narrowed down
      (
        file.size < 4000
        AND file.path LIKE "/tmp/%.sh"
      )
      OR (
        file.size < 4000
        AND file.path LIKE "/tmp/%.py"
      )
    )
  )
  -- Nix
  AND NOT (
    file.directory LIKE "/tmp/tmp%"
    AND gid = 0
    AND uid > 300
    AND uid < 350
  )
  AND NOT magic.data LIKE "%nix-shell script%"
  -- Don't alert if the file is only on disk for a moment
  AND NOT (
    file.directory LIKE "/tmp/%"
    AND (strftime('%s', 'now') - ctime) < 60
  )
  -- macOS updates
  AND NOT file.directory LIKE "/tmp/msu-target-%"
  -- I don't know man. I don't work here.
  AND NOT (file.path LIKE ("/tmp/%compressed") AND size < 4000 AND uid>500)
  -- Executables too small to even hold "#!/bin/sh\nuid"
  AND NOT (file.type = "regular" AND size < 10)