173 lines
4.8 KiB
SQL
173 lines
4.8 KiB
SQL
-- Find unexpected executables in temp directories, often used by malware droppers
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--
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-- false positives:
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-- * developers building code out of /tmp
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--
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-- tags: persistent
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-- platform: linux
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SELECT DISTINCT
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file.path,
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uid,
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gid,
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mode,
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REGEX_MATCH (file.filename, '.*\.(.*?)$', 1) AS extension,
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file.btime,
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file.ctime,
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file.mtime,
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file.size,
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hash.sha256,
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magic.data
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FROM
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file
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LEFT JOIN hash on file.path = hash.path
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LEFT JOIN magic ON file.path = magic.path
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WHERE -- Optimization: don't join things until we have a whittled down list of files
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file.path IN (
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SELECT DISTINCT
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path
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FROM
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file
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WHERE
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(
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file.directory = '/tmp'
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OR file.directory LIKE '/tmp/%'
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OR file.directory LIKE '/tmp/%/%'
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OR file.directory LIKE '/tmp/%/.%'
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OR file.directory LIKE '/tmp/.%'
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OR file.directory LIKE '/tmp/.%/%'
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or file.directory LIKE '/tmp/.%/.%'
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) -- Prevent weird recursion
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AND NOT file.directory LIKE '%/../%'
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AND NOT file.directory LIKE '%/./%' -- Exclude very temporary files
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AND NOT (strftime('%s', 'now') - ctime) < 60 -- Only executable files
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AND file.type = 'regular'
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AND (
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file.mode LIKE '%7%'
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or file.mode LIKE '%5%'
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or file.mode LIKE '%1%'
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)
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AND NOT (
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uid > 500
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AND (
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file.path LIKE '%/go-build%'
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OR file.directory LIKE '/tmp/%/out'
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OR file.path LIKE '%/bin/%'
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OR file.path LIKE '%/checkout/%'
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OR file.path LIKE '%/ci/%'
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OR file.path LIKE '%/debug/%'
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OR file.path LIKE '%/dist/%'
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OR file.path LIKE '%/flow/%.npmzS_cacachezStmpzSgit-clone%'
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OR file.path LIKE '%/git/%'
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OR file.path LIKE '%/github/%'
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OR file.path LIKE '%/go.%.sum'
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OR file.path LIKE "%/%/gradlew"
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OR file.path LIKE '%/guile-%/guile-%'
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OR file.path LIKE '%/ko/%'
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OR file.path LIKE '%/kots/%'
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OR file.path LIKE "%/lib/%.so"
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OR file.path LIKE "%/lib/%.so.%"
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OR file.path LIKE '%/pdf-tools/%'
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OR file.path LIKE '%-release%/%'
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OR file.path LIKE '%/site-packages/markupsafe/_speedups.cpython-%'
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OR file.path LIKE '%/src/%'
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OR file.path LIKE '%/target/%'
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OR file.path LIKE '%/terraformer/%'
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OR file.path LIKE '%/tmp/epdf%'
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)
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) -- Nix
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AND NOT (
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file.directory LIKE '/tmp/tmp%'
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AND gid = 0
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AND uid > 300
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AND uid < 350
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) -- Babel
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AND NOT (
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file.directory LIKE '/tmp/babel-%/sh-script-%'
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AND gid > 900
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AND uid = 1000
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AND size < 1024
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) -- Random Testdata
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AND NOT (
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gid > 900
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AND uid = 1000
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AND (
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file.directory LIKE '/tmp/%/test'
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OR file.directory LIKE '/tmp/%/testdata'
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)
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) -- Don't alert if the file is only on disk for a moment
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AND NOT (
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uid > 500
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AND file.path LIKE '/tmp/terraform_%/terraform'
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)
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AND NOT (
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file.path LIKE '/tmp/%compressed'
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AND size < 4000
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AND uid > 500
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) -- Executables too small to even hold '#!/bin/sh\nuid'
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AND NOT (
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file.type = 'regular'
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AND size < 10
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) -- Weird cert
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AND NOT (
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file.path LIKE '/tmp/tmp.%/ssl/default-fake-certificate.pem'
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AND file.size < 4096
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) -- Binaries we might actually see legitimately
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AND NOT (
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file.path LIKE '/tmp/%'
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AND file.uid > 500
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AND (
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file.filename LIKE "%ctl"
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OR file.filename LIKE "%adm"
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OR file.filename LIKE "%-cli"
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)
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)
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AND NOT (
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file.directory LIKE "%/lib"
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OR file.directory LIKE "%/lib64"
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AND file.uid > 500
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AND (
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file.filename LIKE "%.so.%"
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OR file.filename LIKE "%.so"
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)
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)
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) -- All checks with magic.data must first check for a lack of NULL value,
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-- otherwise you filter out platforms without magic.data.
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AND NOT (
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file.uid > 500
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AND magic.data IS NOT NULL
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AND (
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magic.data IN (
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"POSIX shell script, ASCII text executable",
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"JSON data"
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)
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OR magic.data LIKE "Unicode text%"
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OR magic.data LIKE "gzip compressed data%" -- Exotic platforms
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OR magic.data LIKE 'ELF 64-bit MSB pie executable, IBM S/390%'
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OR magic.data LIKE 'ELF 32-bit LSB pie executable, ARM, EABI5%'
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)
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)
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AND NOT (
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file.size < 50000
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AND file.uid > 500
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AND file.filename LIKE "%.%"
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AND extension IN (
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'adoc',
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'bat',
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'java',
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'js',
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'json',
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'log',
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'nib',
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'pem',
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'perl',
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'pl',
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'py',
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'script',
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'sh',
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'strings',
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'txt',
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'yaml',
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'yml'
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)
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)
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