Increase maldet speed

Anyone who deals professionally with web hosting knows the threat posed by infected users with malware, web shells etc. In the general case it is used maldet a not bad script. It is distinguished by 3 things

  1. It's terribly slow
  2. It's terribly slow and if you put it in monitoring mode it will mess with your server
  3. Supports own database with md5 / hex definitions for bad code.

It is its last feature that makes it useful, because, among other things, you can submit files that have not been detected so far and will enter the databases at a later stage.. As I shared in point 1 and 2 its speed is shockingly low – at low machine load, 70k files were scanned in about an hour and a half. For this reason, I started helping my good friend ShadowX with Malmo – an alternative to maldet written in python with a little more flexibility. Unfortunately for lack of time (mainly but not only) we have not completed the project, which is not very usable at the moment – there are a lot of bugs that need to be cleared. In the past few days I had problems with clients infected with CryptoPHP who had huge public_html files ~ 60k + user inods. Since a total of over 200k files had to be scanned, which would take roughly 5+ hours I decided to tune the configuration of maldet, to reduce the files that will be scanned to a reasonable number and time. As I picked up the conf, I noticed the following lines

# Attempt to detect the presence of ClamAV clamscan binary
# and use as default scanner engine; up to four times faster
# scan performance and superior hex analysis. This option
# only uses ClamAV as the scanner engine, LMD signatures
# are still the basis for detecting threats.
# [ 0 = disabled, 1 = enabled; enabled by default ]
clamav_scan=1

Interesting… Apparently there is an opportunity to use ClamAV – which also does not differ in its high speed, but why not give it a try. I quickly installed it

/scripts/update_local_rpm_versions --edit target_settings.clamav installed

/scripts/check_cpanel_rpms --fix --targets=clamav

I run the maldet on a small folder – I don't see a difference in speed and behavior – he used his perl scanner instead of the clamav. After a short digging through the source of maldet, I found the following lines

 clamscan=`which clamscan 2> /dev/null`
 if [ -f "$clamscan" ] && [ "$clamav_scan" == "1" ]; then
        eout "{scan} found ClamAV clamscan binary, using as scanner engine..." 1
    for hit in `$clamscan -d $inspath/sigs/rfxn.ndb -d $inspath/sigs/rfxn.hdb $clamav_db -r --infected --no-summary -f $find_results 2> /dev/null | tr -d ':' | sed 's/.UNOFFICIAL//' | awk '{print$2":"$1}'`; do

Hmmm, I made one which clamscan and to my great surprise I found that clamav is not in the PATH at all, but the stupid Cpanel left it only in / usr / local / cpanel / 3rdparty / bin / from where he uses his binaries. A quick ln solved the problem:

ln -s /usr/local/cpanel/3rdparty/bin/clamscan /usr/bin/clamscan

When re-scanning, maldet already reports the above

{scan} found ClamAV clamscan binary, using as scanner engine...

After already using ClamAV maldet, it finishes its scan 3-4-5 times faster than before. The test showed – 70k inod-a rubbed them for about 25 min which is about 3 times and a half faster than before.

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