Clamscan process running in background, outside of cron schedule

[msklut]

I've setup a cron job to run a nightly scan at 1am. However, throughout the day our server shows clamscan processes running. We've disabled the "ClamAV Daemon" in Service Configuration » Service Manager and nothing is checked in the ClamAV Scanner Configuration. Why are we seeing clamscan processes like during the day?
top
28019 root 38 18 796308 555960 4264 R 99.3 14.3 0:05.84 /usr/local/cpanel/3rdparty/bin/clamscan
28019 root 38 18 1302712 989684 4428 R 99.7 25.5 0:17.75 /usr/local/cpanel/3rdparty/bin/clamscan
28189 root 38 18 693904 461972 4260 R 99.7 11.9 0:04.11 /usr/local/cpanel/3rdparty/bin/clamscan --max-filesize=6947618 --max-scansize+
30720 root 38 18 1415568 1.0g 4772 R 97.0 28.3 0:25.15 /usr/local/cpanel/3rdparty/bin/clamscan --max-filesize=6947618 --max-scansize+

crontab
0 1 * * * /usr/local/cpanel/3rdparty/bin/clamscan -i -r /home/home_directory/public_html/ | mail -s "ClamAV Scan" [email protected]
47 21 * * * /usr/local/cpanel/3rdparty/bin/freshclam --quiet --no-warnings
0 1 * * * /usr/local/maldetect/maldet -a /home/umuajtmy | mail -s "maldet scan" [email protected]

 

[cPRex]

Hey there! That's interesting - it certainly *looks* like that is the main clamscan process. If you run this, what do you see?

ps aux | grep clamscan

 

[msklut]

Hey there! That's interesting - it certainly *looks* like that is the main clamscan process. If you run this, what do you see?

ps aux | grep clamscan

# ps aux | grep clamscan
root 20505 0.0 0.0 112808 976 pts/0 S+ 10:47 0:00 grep --color=auto clamscan

 

[cPRex]

Thanks for that. That would indicate there are currently no processes running, so as of right now I wouldn't expect to see them in "top" either. Is it possible the cron job is just taking longer than expected to run?

 

[msklut]

Thanks for that. That would indicate there are currently no processes running, so as of right now I wouldn't expect to see them in "top" either. Is it possible the cron job is just taking longer than expected to run?

The clamscan processes that show in 'top' are later in the day, many hours after the cron job has completed. I actually just ran ps aux grep when I noticed a clamscan process in 'top'. Here's the output:

# ps aux | grep clamscan
root 23999 115 12.5 720016 488376 ? RN 11:22 0:04 /usr/local/cpanel/3rdparty/bin/clamscan --max-filesize=6947618 --max-scansize=13895236 -d /usr/local/maldetect/tmp/.runtime.user.876.hdb -d /usr/local/maldetect/tmp/.runtime.user.876.ndb -d /var/clamav/ -r --infected --no-summary -f /usr/local/maldetect/tmp/.monitor.scan.85789128
root 24003 0.0 0.0 112808 972 pts/1 S+ 11:22 0:00 grep --color=auto clamscan

 

[msklut]

It looks like LMD may be the issue. I've included the LMD config file below:

#
##
# Linux Malware Detect v1.6.4
# (C) 2002-2019, R-fx Networks <[email protected]>
# (C) 2019, Ryan MacDonald <[email protected]>
# This program may be freely redistributed under the terms of the GNU GPL v2
##
#
##
# [ General Options ]
##

# Enable or disable e-mail alerts, this includes application version
# alerts as well as automated/manual scan reports. On-demand reports
# can still be sent using '--report SCANID [email protected]'.
# [0 = disabled, 1 = enabled]
email_alert="1"

# The destination e-mail addresses for automated/manual scan reports
# and application version alerts.
# [ multiple addresses comma (,) spaced ]
email_addr="[email protected]"

# Ignore e-mail alerts for scan reports in which all malware hits
# have been automatically and successfully cleaned.
# [0 = disabled, 1 = enabled]
email_ignore_clean="1"

# This controls the daily automatic updates of LMD signature files
# and cleaner rules. The signature update process preserves any
# custom signature or cleaner files. It is highly recommended that this
# be enabled as new signatures a released multiple times per-week.
# [0 = disabled, 1 = enabled]
autoupdate_signatures="1"

# This controls the daily automatic updates of the LMD installation.
# The installation update process preserves all configuration options
# along with custom signature and cleaner files. It is recommended that
# this be enabled to ensure the latest version, features and bug fixes
# are always available.
# [0 = disabled, 1 = enabled]
autoupdate_version="1"

# This controls validating the LMD executable MD5 hash with known
# good upstream hash value. This allows LMD to replace the the
# executable / force a reinstallation in the event the LMD executable
# is tampered with or corrupted. If you intend to make customizations
# to the LMD executable, you should disable this feature.
# [0 = disabled, 1 = enabled]
autoupdate_version_hashed="1"

# The retention period, in days, which quarantine, temporary files and stale
# session information should be retained. Data older than this value is deleted
# with the daily cron execution.
cron_prune_days="21"

# This controls whether or not daily automatic scanning of standard web
# directories is performed via cron.
# [0 = disabled, 1 = enabled]
cron_daily_scan="1"

# When defined, the import_config_url option allows a configuration file to be
# downloaded from a remote URL. The local conf.maldet and internals.conf are
# parsed followed by the imported configuration file. As such, only variables
# defined in the imported configuration file are overridden and a full set of
# configuration options is not explicitly required in the imported file.
import_config_url=""

# The expiry interval for refreshing the local cached version of the imported
# configuration file. The default is every 12h (43200 sec) which should be ok
# for most setups.
import_config_expire="43200"

# When defined, the import_custsigs_*_url options allow for the custom signature
# files to be downloaded from a remote URL. THIS WILL OVERWRITE ANY LOCAL CUSTOM
# SIGNATURE FILES! It is recommended for large-scale deployments to define these
# variables within a import_config_url file.
import_custsigs_md5_url=""
import_custsigs_hex_url=""

##
# [ SCAN OPTIONS ]
##

# The maximum directory depth that the scanner will search, a value
# of 15 is recommended.
# [ changing this may have an impact on scan performance ]
scan_max_depth="15"

# The minimum file size in bytes for a file to be included in LMD scans.
# [ changing this may have an impact on scan performance ]
scan_min_filesize="24"

# The maximum file size for a file to be included in LMD scans. Accepted
# value formats are b, k, M. When using the clamscan engine, the max_filesize
# will be dynamically set based on the largest known filesize from the MD5
# hash signature file.
# [ changing this may have an impact on scan performance ]
scan_max_filesize="2048k"

# The maximum byte depth that the scanner will search into a files content.
# The default signature rules expect a depth size of at least 65536 bytes.
# [ changing this may have an impact on scan performance ]
scan_hexdepth="65536"

# Use named pipe (FIFO) for passing file contents hex data instead of stdin
# default; improved performance and greater scanning depth. This is highly
# recommended and works on most systems. The hexfifo will be disabled
# automatically if for any reason it can not be successfully utilized.
# [ 0 = disabled, 1 = enabled ]
scan_hexfifo="1"

# The maximum byte depth that the scanner will search into a files content
#s when using named pipe (FIFO). Improved performance allows for greater
# scan depth over default scan_hexdepth value.
# [ changing this may have an impact on scan performance ]
scan_hexfifo_depth="524288"

# If installed, use ClamAV clamscan binary as default scan engine which
# provides improved scan performance on large file sets. The clamscan
# engine is used in conjunction with native ClamAV signatures updated
# through freshclam along with LMD signatures providing additional
# detection capabilities.
# [ 0 = disabled, 1 = enabled ]
scan_clamscan="1"

# Include the scanning of known temporary world-writable paths for
# -a|--al and -r|--recent scan types.
scan_tmpdir_paths="/tmp /var/tmp /dev/shm"

# Allows non-root users to perform scans. This must be enabled when
# using mod_security2 upload scanning or if you want to allow users
# to perform scans. When enabled, this will populate 'pub/' with user
# owned quarantine, session and temporary paths to facilitate scans.
# [ 0 = disabled, 1 = enabled, disabled by default ]
scan_user_access="0"

# Process CPU scheduling (nice) priority level for scan operations.
# [ -19 = high prio , 19 = low prio, default = 19 ]
scan_cpunice="19"

# Process IO scheduling (ionice) priority levels for scan operations.
# (uses cbq best-effort scheduling class [-c2])
# [ 0 = most favorable IO, 7 = least favorable IO ]
scan_ionice="6"

# Set hard limit on CPU usage for find and clam(d)scan processes. This
# requires the 'cpulimit' binary to be available on the server. The values
# are expressed as relative percentage * N cores on system. An 8 CPU core
# server would accept values from 0 - 800, 12 cores 0 - 1200 etc...
scan_cpulimit="0"

# As a design and common use case, LMD typically only scans user space paths
# and as such it makes sense to ignore files that are root owned. It is
# recommended to leave this enabled for best performance.
# [ 0 = disabled, 1 = enabled ]
scan_ignore_root="1"

# This allows for specific user or groups to be ignored entirely from scan
# file lists. This option should be used with care and is not ideal for
# ignoring false positives. Instead, you should use one of the ignore files,
# such as ignore_paths, to exclude a specific file name or path from scans.
# [ comma or white spaced list of user and group names ]
scan_ignore_user=""
scan_ignore_group=""

# The maximum amount of time, in seconds, that the 'find' file list generation
# will run before it is terminated. All 'find' results up to the point of
# termination will be fully scanned. If performing a full scan of all user paths
# on a large server, it is reasonable to expect the find operation may take a
# long time to complete and as such this feature may interfere. In such cases,
# this feature can be disabled/modified on a per-scan basis using the
# '-co|--config-option' CLI option, such as:
# "maldet -co scan_find_timeout=0 -a /home/?/public_html".
# [ 0 = disabled, 14400 = 4hr recommended timeout ]
scan_find_timeout="0"

# The daily cron 'find' operation performed by LMD detects recently created/modifed
# user files. This 'find' operation can be especially resource intensive and it may
# be desirable to persist the file list results so that other applications/tasks
# may make use of the results. When scan_export_filelist is set enabled, the most
# recent result set will be saved to '/usr/local/maldetect/tmp/find_results.last'
# [ 0 = disabled, 1 = enabled ]
scan_export_filelist="0"

##
# [ QUARANTINE OPTIONS ]
##
# The default quarantine action for malware hits
# [0 = alert only, 1 = move to quarantine & alert]
quarantine_hits="1"

# Try to clean string based malware injections
# [NOTE: quarantine_hits=1 required]
# [0 = disabled, 1 = clean]
quarantine_clean="1"

# The default suspend action for users wih hits
# Cpanel suspend or set shell /bin/false on non-Cpanel
# [NOTE: quarantine_hits=1 required]
# [0 = disabled, 1 = suspend account]
quarantine_suspend_user="0"

# The minimum userid value that can be suspended
# [ default = 500 ]
quarantine_suspend_user_minuid="500"

# When using an external scan engine, such as ClamAV, should files be
# quarantined if an error from the scanner engine is received?
# This is defaulted to 1, always quarantine, as ClamAV generates an
# error exit code for trivial errors such as file not found. As such, a
# large percentage of scans will have ClamAV exiting with error code 2.
# [ 0 = do not quarantine, 1 = always quarantine ]
quarantine_on_error="1"

##
# [ MONITORING OPTIONS ]
##
# The default startup option for monitor mode, either 'users' or path to line
# spaced file containing local paths to monitor.
#
# This option is optional for the init based startup script, maldet.sh. This
# value is ignored when '/etc/sysconfig/maldet' or '/etc/default/maldet' is
# present with a defined value for .
#
# This option is REQUIRED for the systemd maldet.service script. That script
# only checks for the value of users. The service will fail to
# start if a value is not provided.
# default_monitor_mode="users"
# default_monitor_mode="/usr/local/maldetect/monitor_paths"
default_monitor_mode="users"

# The base number of files that can be watched under a path
# [ maximum file watches = inotify_base_watches*users ]
inotify_base_watches="16384"

# The sleep time in seconds between monitor runs to scan files
# that have been created/modified/moved
inotify_sleep="30"

# The interval in seconds that inotify will reload configuration
# data, including remote configuration imports.
inotify_reloadtime="3600"

# The minimum userid that will be added to path monitoring when
# the USERS option is specified
inotify_minuid="500"

# This is the html/web root for users relative to homedir, when
# this option is set, users will only have the webdir monitored
# [ comma spaced list, clear option to default monitor user homedir ]
inotify_docroot="public_html,public_ftp"

# Process CPU scheduling (nice) priority level for monitoring process.
# [ -19 = high prio , 19 = low prio, default = 15 ]
inotify_cpunice="18"

# Process IO scheduling (ionice) priority levels for scan operations.
# (uses cbq best-effort scheduling class [-c2])
# [ 0 = most favorable IO, 7 = least favorable IO ]
inotify_ionice="6"

# Set hard limit on CPU usage for inotify monitoring processes. This requires
# the 'cpulimit' binary to be available on the server. The values are expressed
# as relative percentage * N cores on system. An 8 CPU core system would accept
# values from 0 - 800, a 12 cores system would accept 0 - 1200 etc...
inotify_cpulimit="0"

# Log every file scanned by inotify monitoring mode; this is not recommended
# and will drown out your 'event_log' file, intended only for debugging purposes.
inotify_verbose="0"

##
# [ STATISTICAL ANALYSIS ]
# This is a beta feature and as such should be used with caution.
# Currently, this feature can have a substantially negative impact
# on scan performance, especially with large file sets.
##
# The string length test is used to identify threats based on the
# length of the longest uninterrupted string within a file. This is
# useful as obfuscated code is often stored using encoding methods
# that produce very long strings without spaces (e.g: base64)
# [ string length in characters, default = 150000 ]
string_length_scan="0" # [ 0 = disabled, 1 = enabled ]
string_length="150000" # [ max string length ]

 

[cPRex]

That would do it!

 

[msklut]

That would do it!

any changes to conf.maldet you recommend?

 

[cPRex]

I don't - cPanel doesn't provide that software so I'm not very familiar with the configuration options for that tool.

 

[msklut]

I increased the inotify_sleep="30" to make the duration longer between monitor runs. So far it seems to have worked well.