ClamAV osquery extension
This extension integrates ClamAV into osquery. Currently this extenion only supports GNU/Linux systems.
Build
This extension currently needs to be built manually and requires libclamav, prebuilt binaries will be provided at a later time. It can be built using the buildsystem from osql
Steps to build:
- Download the source code for osql, https://github.com/osql/osql
git clone https://github.com/osql/osql
- Download the source code for clamav-osquery
git clone https://github.com/puffyCid/clamav-osquery - Move extension_clamav to osql/external
- Run make sysprep, make deps, make. Further explanation can be found at https://osquery.readthedocs.io
- Make root the owner of the extension
- Place config.json at /usr/lib/osquery/extensions/clamav/
- Optionally, place the compiled extension, clamav_ext.ext, at /usr/lib/osquery/extensions/clamav/
Usage
Osquery needs to run as root when executing the ClamAV extension. When first executed the extension will attempt to download the official clamav databases from database.clamav.net. The databases will be downloaded to /usr/lib/osquery/extensions/clamav/clamdbs/
The config.json file controls several settings of the extension:
- url: Url to download ClamAV databases. Right now the extension is hardcoded to download main.cvd, daily.cvd, and bytecode.cvd.
- port: Port to connect to the url.
- time: How often the extensiono should update the ClamAV databases. By default the extension will update the databases every 7 days.
- update: Whether the extension should update databases. Set it to false to disable updates.
When executed the extension will load the ClamAV databases into memory, this will cause the extension to use a large amount of RAM ~680MB. Once the extension is done executing it releases the databases from memory.
This extension has been tested on:
- Debian 9 (Stretch)
- Centos 7
- OpenSUSE Tumbleweed
Example queries
Scan one file
select * from clamav where path = "/home/puffycid/Downloads/osquery_test/rootkit.ex1";
+---------------------------------------------------+-------------+---------+-----------------------+
| path | filename | malware | malware_name |
+---------------------------------------------------+-------------+---------+-----------------------+
| /home/puffycid/Downloads/osquery_test/rootkit.ex1 | rootkit.ex1 | true | Win.Trojan.Lancafdo-1 |
+---------------------------------------------------+-------------+---------+-----------------------+
Scan multiple files and hash the files
select clamav.*, hash.md5, file.size from clamav JOIN hash using (path) JOIN file using (path) where clamav.path like "/home/puffycid/Downloads/%%/%" and size < 1024000;
+-------------------------------------------------------------------------------------------------------+------------------------------------------------------------------+---------+-----------------------------+----------------------------------+--------+
| path | filename | malware | malware_name | md5 | size |
+-------------------------------------------------------------------------------------------------------+------------------------------------------------------------------+---------+-----------------------------+----------------------------------+--------+
| /home/puffycid/Downloads/osquery_test/29D6161522C7F7F21B35401907C702BDDB05ED47.bin_ | 29D6161522C7F7F21B35401907C702BDDB05ED47.bin_ | true | Win.Trojan.Emotet-6799923-0 | 8baa9b809b591a11af423824f4d9726a | 96535 |
| /home/puffycid/Downloads/osquery_test/Memorydump.js | Memorydump.js | false | | 3b4372cd94265c325997bc3e8f8d03aa | 505 |
| /home/puffycid/Downloads/osquery_test/rootkit.ex1 | rootkit.ex1 | true | Win.Trojan.Lancafdo-1 | 9219e2cfcc64ccde2d8de507538b9991 | 76288 |
| /home/puffycid/Downloads/osquery_test/test.cpp | test.cpp | false | | 94547e937001cf164e1fcab8ae963ae1 | 1400 |
+-------------------------------------------------------------------------------------------------------+------------------------------------------------------------------+---------+-----------------------------+----------------------------------+--------+
Example Kolide query
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