Building an ICAP enabled AntiVirus Server based on c-icap, ClamAV and Alpine Linux on Proxmox PVE/LXC container.
The idea of this project is to create an Alpine based LXC container that will host:
- c-icap server as our HTTP proxy ICAP content adaptation and filtering services.
- SquidClamAV compiled & enabled as an ICAP service.
- ClamAV as our backend AntiVirus scanning system upon ICAP submissions.
- The ClamAV official signatures databases.
- 3rd party unofficial ClamAV signatures databases enhancing our defenses.
Basically, the ideal Proxy Server's companion thus offloading all the on-the-fly AntiVirus tasks through ICAP.
- eth0 should be bound/connected to unfiltered WAN (a WAN/DMZ LAN/VLAN)
- eth1 should be bound/connected to where you'd like to engage/connect through ICAP on TCP:1344 (your Proxy LAN/VLAN or such)
+-----------------------------------------------------+
| cICAP Alpine LXC |
| |
| +-------------+ |
| | ClamAV | |
| | ClamD | |
| +-------------+ +-------------+ |
| | freshclam | | c-icap | |
| | signatures | | | |
| | updates | | | |
| +-------------+ +-------------+ |
|-----------------------------------------------------|
eth0/WAN| ||| | | ||| |eth1/LAN
+-----+ +-----+tcp:1344
| |
| |
0.0.0.0/0 Proxy / ICAP Client
10/8
172.16/12
192.168/16
This implementation has been influenced by this repository c_icapClamav which is held toward Docker environments. I do not "dislike" Docker at all, although as I'm running PVE in my personal setups, I find PVE + LXC very handy and convenient in terms of updates, backups and so on. Docker in my own setups pretty much always means two or more layers of virtualization, which I tend to avoid if not purely for demo's etc.
A few notes before you start:
- You might use Squid as your main proxy server -- mind that the Squid ICAP integration/implementation is beyond our scope here. You'll find more information about this here.
- Obviously, you can submit to ICAP what you can read & see, therefore SSL Bumping/SSL interception might be advised on your proxy subsystem in order to "intercept" SSL/TLS encrypted streams.
- The
ConcurrentDatabaseReload yesparameter which is set within/etc/clamav/clamd.confwill require you to have enough free system resources (2x operational used memory, 4GB shall be enough) in order to temporarily load a second ClamAV scanning engine while scanning continues using the first engine. Once fully loaded, the new engine takes over while the previous goes to heaven. - You're able to address either SquidClamAV service [OR] the srv_clamav c-icap service, which can be useful for testings etc.
MALWARE_FOUNDreplacement HTML page has been customized in order to provide a somewhat better looking block page in the occurrence of offending bits found by ClamAV (see below).
You can use the included cicap-deploy.sh shell script to deploy/compile everything needed at once.
pveam update
pveam available | grep alpine
pveam download local alpine-3.20-default_20240908_amd64.tar.xz
Create your PVE LXC container -- A typical PVE LXC container PVE cli that would suite our needs: (mind the container ID, admin password, bound bridges, vlan tags, IPs etc.. adapt to your environment):
pct create 100 local:vztmpl/alpine-3.20-default_20240908_amd64.tar.xz \
--storage local-lvm --ostype alpine \
--arch amd64 --password ChangeMe --unprivileged 1 \
--cores 4 --memory 4096 --swap 4096 \
--hostname cICAP --rootfs volume=local-lvm:16 \
--nameserver 9.9.9.9 --searchdomain local.lan \
--net0 name=eth0,bridge=vmbr1,tag=100,ip=192.168.13.44/24,gw=192.168.1.254,type=veth \
--net1 name=eth1,bridge=vmbr9,tag=999,ip=10.1.13.44/24,type=veth \
--start false
pct start 100
There are two options using the deployment script provided:
- Deploy Alpine Linux distribution using the
/main/repository - Deploy Alpine Linux distribution using the
/edge/repository
The main differences are the apk packages retrieved, the /main/ repository currently host ClamAV 1.2.2-r0 while the /edge/ host the ClamAV 1.3.2-r0 package.
The provided script will do everything in one shot -- You need to create & boot your container (see above) and get the script contents in a local file and run it (see below).
mkdir -p /tmp/install && cd /tmp/install
wget https://raw.githubusercontent.com/obuno/LXC_cICAP_ClamAV/main/cicap-deploy.sh
sh cicap-deploy.sh
I.E. running the deployment script and opting for the /edge/ Alpine repository:
; ####################################################
; ###### cICAP deployment START ######################
; ####################################################
; ####################################################
; ###### cICAP system status CHECK ###################
; ####################################################
[*] Your system host multiple NICs, is this correct? (Y/n) y
; ####################################################
; ###### apk update & add ############################
; ####################################################
[*] Do you want to use the Alpine Edge Repository? (Y/n) y --> Answering NO here will get you /latest-stable/ Alpine setup.
...
cICAP:~# ls -lsah /var/lib/clamav/
total 373M
4.0K drwxr-xr-x 2 clamav clamav 4.0K Feb 18 16:08 .
4.0K drwxr-xr-x 7 root root 4.0K Feb 18 16:02 ..
4.0K -rw-r--r-- 1 clamav clamav 1.4K Feb 18 16:08 Sanesecurity_sigtest.yara
4.0K -rw-r--r-- 1 clamav clamav 1.2K Feb 18 16:08 Sanesecurity_spam.yara
108.0K -rw-r--r-- 1 clamav clamav 107.4K Feb 18 16:08 badmacro.ndb
312.0K -rw-r--r-- 1 clamav clamav 308.2K Feb 18 16:08 blurl.ndb
4.0K -rw-r--r-- 1 clamav clamav 3.4K Feb 18 16:08 bofhland_cracked_URL.ndb
4.0K -rw-r--r-- 1 clamav clamav 610 Feb 18 16:08 bofhland_malware_URL.ndb
104.0K -rw-r--r-- 1 clamav clamav 103.8K Feb 18 16:08 bofhland_malware_attach.hdb
12.0K -rw-r--r-- 1 clamav clamav 9.4K Feb 18 16:08 bofhland_phishing_URL.ndb
288.0K -rw-r--r-- 1 clamav clamav 285.1K Feb 18 16:08 bytecode.cvd
76.0K -rw-r--r-- 1 clamav clamav 72.5K Feb 18 16:08 clamav.ldb
4.0K -rw-r--r-- 1 clamav clamav 82 Feb 18 16:08 crdfam.clamav.hdb
190.2M -rw-r--r-- 1 clamav clamav 190.2M Feb 18 16:07 daily.cld
4.0K -rw-r--r-- 1 clamav clamav 69 Feb 18 16:07 freshclam.dat
48.0K -rw-r--r-- 1 clamav clamav 47.0K Feb 18 16:08 hackingteam.hsb
8.0K -rw-r--r-- 1 clamav clamav 5.8K Feb 18 16:08 indicator_rmm.ldb
6.8M -rw-r--r-- 1 clamav clamav 6.8M Feb 18 16:08 junk.ndb
3.3M -rw-r--r-- 1 clamav clamav 3.3M Feb 18 16:08 jurlbl.ndb
88.0K -rw-r--r-- 1 clamav clamav 86.4K Feb 18 16:08 jurlbla.ndb
240.0K -rw-r--r-- 1 clamav clamav 239.9K Feb 18 16:08 lott.ndb
162.6M -rw-r--r-- 1 clamav clamav 162.6M Feb 18 16:07 main.cvd
100.0K -rw-r--r-- 1 clamav clamav 98.5K Feb 18 16:08 malwarehash.hsb
4.3M -rw-r--r-- 1 clamav clamav 4.3M Feb 18 16:08 phish.ndb
4.0K -rw-r--r-- 1 clamav clamav 107 Feb 18 16:08 phishtank.ndb
24.0K -rw-r--r-- 1 clamav clamav 21.8K Feb 18 16:08 porcupine.hsb
172.0K -rw-r--r-- 1 clamav clamav 168.9K Feb 18 16:08 porcupine.ndb
856.0K -rw-r--r-- 1 clamav clamav 852.6K Feb 18 16:08 rfxn.hdb
444.0K -rw-r--r-- 1 clamav clamav 443.4K Feb 18 16:08 rfxn.ndb
704.0K -rw-r--r-- 1 clamav clamav 700.4K Feb 18 16:08 rogue.hdb
16.0K -rw-r--r-- 1 clamav clamav 12.2K Feb 18 16:08 sanesecurity.ftm
1.9M -rw-r--r-- 1 clamav clamav 1.9M Feb 18 16:08 scam.ndb
12.0K -rw-r--r-- 1 clamav clamav 9.3K Feb 18 16:08 shelter.ldb
4.0K -rw-r--r-- 1 clamav clamav 488 Feb 18 16:08 sigwhitelist.ign2
4.0K -rw-r--r-- 1 clamav clamav 115 Feb 18 16:08 spear.ndb
4.0K -rw-r--r-- 1 clamav clamav 115 Feb 18 16:08 spearl.ndb
4.0K -rw-r--r-- 1 clamav clamav 64 Feb 18 16:08 winnow.attachments.hdb
4.0K -rw-r--r-- 1 clamav clamav 660 Feb 18 16:08 winnow.complex.patterns.ldb
4.0K -rw-r--r-- 1 clamav clamav 66 Feb 18 16:08 winnow_bad_cw.hdb
4.0K -rw-r--r-- 1 clamav clamav 65 Feb 18 16:08 winnow_extended_malware.hdb
4.0K -rw-r--r-- 1 clamav clamav 159 Feb 18 16:08 winnow_extended_malware_links.ndb
4.0K -rw-r--r-- 1 clamav clamav 65 Feb 18 16:08 winnow_malware.hdb
16.0K -rw-r--r-- 1 clamav clamav 14.4K Feb 18 16:08 winnow_malware_links.ndb
8.0K -rw-r--r-- 1 clamav clamav 6.4K Feb 18 16:08 winnow_phish_complete_url.ndb
4.0K -rw-r--r-- 1 clamav clamav 2.7K Feb 18 16:08 winnow_spam_complete.ndb
cICAP:~# clamscan --debug 2>&1 /dev/null | grep "loaded"
LibClamAV debug: unrar support loaded from /usr/lib/libclamunrar_iface.so.12.0.2
LibClamAV debug: /var/lib/clamav/localwhitelist.ign2 loaded
LibClamAV debug: /var/lib/clamav/sigwhitelist.ign2 loaded
LibClamAV debug: daily.info loaded
LibClamAV debug: daily.cfg loaded
LibClamAV debug: daily.ndb loaded
LibClamAV debug: daily.crb loaded
LibClamAV debug: daily.ign loaded
LibClamAV debug: daily.mdb loaded
...
cICAP:~#
cICAP:~# ps
PID USER TIME COMMAND
...
534 clamav 0:26 /usr/sbin/clamd
562 cicap 0:00 /opt/c-icap/bin/c-icap -D -d 5
564 cicap 0:00 /opt/c-icap/bin/c-icap -D -d 5
565 cicap 0:00 /opt/c-icap/bin/c-icap -D -d 5
571 cicap 0:00 /opt/c-icap/bin/c-icap -D -d 5
...
cICAP:~# rc-status
Runlevel: default
...
c-clamd [ started ]
c-icap [ started ]
...
cICAP:~#
cICAP:~# ss -utnlp
Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port Process
tcp LISTEN 0 512 10.1.13.44:1344 0.0.0.0:* users:(("c-icap",pid=596,fd=5),("c-icap",pid=590,fd=5),("c-icap",pid=589,fd=5),("c-icap",pid=587,fd=5))
cICAP:~#
cICAP:~#
Confirming our c-icap server is operating correctly (assuming your Proxy <--> c-icap integration is functional):
cICAP:~# tail -f /var/log/c-icap/server.log
TransferPreview: "Transfer-Preview: *"
TransferIgnore:
TransferComplete:
Max-Connections: -1
Wed Apr 10 06:16:13 2024, 763/134926734121784, squidclamav.c(331) squidclamav_release_request_data: Wed Apr 10 06:16:13 2024, 763/134926734121784, DEBUG Releasing request data.
Wed Apr 10 06:16:13 2024, 763/134926734121784, connection closed or request timed-out or request interrupted....
Wed Apr 10 06:16:13 2024, 763/134926734981944, connection closed or request timed-out or request interrupted....
Wed Apr 10 06:16:19 2024, 769/134926734695224, connection closed or request timed-out or request interrupted....
Wed Apr 10 06:16:19 2024, 769/134926734981944, connection closed or request timed-out or request interrupted....
Wed Apr 10 06:16:19 2024, 769/134926734981944, Max requests reached, reallocate memory and buffers .....
Wed Apr 10 06:16:47 2024, 763/134926734838584, squidclamav.c(304) squidclamav_init_request_data: Wed Apr 10 06:16:47 2024, 763/134926734838584, DEBUG initializing request data handler.
Wed Apr 10 06:16:47 2024, 763/134926734838584, squidclamav.c(359) squidclamav_check_preview_handler: Wed Apr 10 06:16:47 2024, 763/134926734838584, DEBUG processing preview header.
Wed Apr 10 06:16:47 2024, 763/134926734838584, squidclamav.c(391) squidclamav_check_preview_handler: Wed Apr 10 06:16:47 2024, 763/134926734838584, DEBUG X-Client-IP: 10.0.0.2
Wed Apr 10 06:16:47 2024, 763/134926734838584, squidclamav.c(1784) extract_http_info: Wed Apr 10 06:16:47 2024, 763/134926734838584, DEBUG method CONNECT
Wed Apr 10 06:16:47 2024, 763/134926734838584, squidclamav.c(1795) extract_http_info: Wed Apr 10 06:16:47 2024, 763/134926734838584, DEBUG url templeos.org:443
...
cICAP:~# run-parts --test /etc/periodic/hourly
/etc/periodic/hourly/freshclam
cICAP:~# cat /var/log/clamav/freshclam-hourly.log
--------------------------------------
ClamAV update process started at Sun Feb 18 17:00:00 2024
daily.cld database is up-to-date (version: 27189, sigs: 2053641, f-level: 90, builder: raynman)
main.cvd database is up-to-date (version: 62, sigs: 6647427, f-level: 90, builder: sigmgr)
bytecode.cvd database is up-to-date (version: 334, sigs: 91, f-level: 90, builder: anvilleg)
...
cICAP:~# c-icap-client -s "info?table=*?view=text" -i [your-icap-bound-ip] -p 1344 -req use-any-url
ICAP server:[your-icap-bound-ip], ip:[your-icap-bound-ip], port:1344
Running Servers Statistics
===========================
Children number: 3
Free Servers: 27
Used Servers: 3
Started Processes: 6
Closed Processes: 3
Crashed Processes: 0
...
- SaneSecurity
- R-fx Networks - Linux Malware Detect
- Ditekshen
- InterServer's InterShield
- URLhaus ClamAV signatures
I would highly recommend you to add/test the following unofficial ClamAV databases to your locally available ClamAV DB's:
- The SecuriteInfo ClamAV databases in "Pro Subscription": https://www.securiteinfo.com/clamav-antivirus/improve-detection-rate-of-zero-day-malwares-for-clamav.shtml?lg=en
You can test your setup using a few available Malware Test sites on the internet:
https://eicar.eu
https://sophostest.com
https://www.amtso.org/security-features-check/
https://www.ikarussecurity.com/wp-content/downloads/eicar_com.zip
https://pkg.opnsense.org/test/eicar.com.txt
https://www.virusanalyst.com/eicar.zip
- the container ready to serve time can take up to 2/3 minutes, all the ClamAV databases are loaded in memory at boot time -- just be patient.
- you're able to restart both involved services using:
rc-service c-icap restart
rc-service c-clamd restart - you can spot presumed false positive signatures by running
icap-logs | grep FOUND - you can view in real time the client IP, requested URL's and potential matching ClamAV signature using
icap-logs | egrep "X-Client-IP|URL requested|FOUND" - should you think that some signatures might trigger on false positive, you're able to whitelist them.
- Within my setup I'm almost always white listing this signature:
Sanesecurity.Foxhole.GZip_jswithin a local file called/var/lib/clamav/localwhitelist.ign2 - for SquidClamAV, the ICAP client should have these properties set accordingly: IP of your container | Service port = TCP:1344 | Service Name = squidclamav | Type = REQMOD or RESPMOD
- for srv_clamav, the ICAP client should have these properties set accordingly: IP of your container | Service port = TCP:1344 | Service Name = srv_clamav | Type = REQMOD or RESPMOD
- the
squidclamav.conffile includes a few 'exclusions' I find appropriate. Perhaps you do not. You can of course edit this file and comment lines in the block after line #88 - installed packages (gcc, g++, make, etc.) are NOT removed. While I'd agree that some of them could/can be removed for security concerns, in my setups, I do not see the need for that. I keep these cICAP appliances off anything else than ICAP_TCP:1344 within the same network segment as any ICAP clients. Should you enable network remote access (ssh etc), please consider the risks of leaving all these packages installed.
- the c-icap service definition fails to stop/restart on the first attempt --> 👍 10/04/2024
- the c-icap service now run's on a non root
cicapsystem user account --> 👍 21/07/2024 - the
/var/log/c-icap/server.logfile get's big over time -- seec-icap-logs-archive--> 👍 21/07/2024 - user experience improvements on the
cicap-deploy.shscript --> 👍 25/11/2024