FW Monitor SuperTool

[Danny]

📕 Referenced in the book: Max Power 2020
▶️ Featured in How to use fw monitor

One-liner (Bash) to assist running fw monitor on Check Point firewall gateways.
In expert mode run:

if [[ `$CPDIR/bin/cpprod_util FwIsFirewallModule 2>/dev/null` != *'1'* ]]; then echo; tput bold; echo ' Not a firewall gateway!'; tput sgr0; echo; else echo; printf '%.s-' {1..60}; echo; echo ' FW Monitor SuperTool'; printf '%.s-' {1..60}; echo; echo; tput bold; echo -n ' Add host IPs '; tput sgr0; echo -n '(leave empty for any): '; read _hosts; b='0'; case $_hosts in '') echo -n '   any '; tput setaf 2; echo 'OK'; tput sgr0;; *) _hosts=($(echo $_hosts | tr ',;:|()#<>' ' ' | tr -s ' ')); for a in ${_hosts[@]}; do if [[ `ipcalc -ms $a` == *'='* ]] && [[ $a == *'.'* ]]; then echo -n '   '$a' '; tput setaf 2; echo 'OK'; b='1'; tput sgr0; else echo -n '   '$a' '; tput setaf 1; echo 'Bad syntax!'; tput sgr0; fi; done; esac; echo; tput bold; echo -n ' Add ports '; tput sgr0; echo -n '(leave empty for any): '; read _ports; d='0'; case $_ports in '') echo -n '   any '; tput setaf 2; echo 'OK'; tput sgr0;; *) _ports=($(echo $_ports | tr ',;:|()#<>' ' ' | tr -s ' ')); for a in ${_ports[@]}; do if [[ $a != *[^0-9]* ]]; then echo -n '   '$a' '; tput setaf 2; echo 'OK'; d='1'; tput sgr0; else echo -n '   '$a' '; tput setaf 1; echo 'Bad syntax!'; tput sgr0; fi; done; esac; echo; tput bold; echo -n ' Add protocol '; tput sgr0; echo -n '(tcp, udp, icmp): '; read _prot; c='0'; case $_prot in '') echo -n '   any '; tput setaf 2; echo 'OK'; tput sgr0;; *) _prot=($(echo $_prot | tr ',;:|()#<>' ' ' | tr -s ' ')); for a in ${_prot[@]}; do case $a in tcp|udp|icmp) echo -n '   '$a' '; tput setaf 2; echo 'OK'; c='1'; tput sgr0;; *) echo -n '   '$a' '; tput setaf 1; echo 'Unknown protocol!'; tput sgr0; esac; done; esac; echo; tput bold; echo -n ' Capture to file '; tput sgr0; read -p '(leave empty for stdout): ' _file; if [[ -n $_file ]]; then tput setaf 2; echo -n '   Saving output to: '; tput sgr0; echo $_file; else tput setaf 2; echo '   Output to CLI'; tput sgr0; fi; echo; printf '%.s-' {1..60}; echo; _sxl='0'; tput setab 1; tput setaf 7; tput bold; echo -n ' Executing ? '; tput sgr0; echo -n ' '; if [[ `fw monitor -h 2>&1` != *'-F'* ]]; then case `fwaccel stat | grep 'Accelerator Status :' | cut -c 22-` in on) _sxl='1'; esac; fi; if [[ $_sxl == '1' ]]; then _run='fwaccel off; fw monitor'; else _run='fw monitor'; fi; if [[ -z $_file ]]; then _run+=' -T'; if [[ `fw monitor -h 2>&1` != *'-F'* ]]; then _run+=' -e "'; if [[ $b == '1' && $d == '1' ]]; then _run+='('; elif [[ $b == '1' && $c == '1' ]]; then _run+='('; fi; for a in ${_hosts[@]}; do if [[ `ipcalc -ms $a` == *'='* ]] && [[ $a == *'.'* ]]; then _run+='host('$a') and '; fi; done; if [[ $b == '1' && $d == '1' ]]; then _run=${_run%?????}; _run+=')'; elif [[ $b == '1' && $c == '1' ]]; then _run=${_run%?????}; _run+=')'; fi; if [[ $b == '1' && $d == '1' ]]; then _run+=' and ('; elif [[ $d == '1' && $c == '1' ]]; then _run+='('; elif [[ $b == '1' && $c == '1' ]]; then _run+=' and ('; fi; for a in ${_ports[@]}; do if [[ $a != *[^0-9]* ]]; then _run+='port('$a') or '; fi; done; if [[ $b == '1' && $d == '1' ]]; then _run=${_run%????}; _run+=')'; elif [[ $d == '1' && $c == '1' ]]; then _run=${_run%????}; _run+=')'; elif [[ $b == '0' && $d == '1' ]]; then _run=${_run%????}; elif [[ $b == '1' && $d == '0' ]]; then _run=${_run%?????}; fi; if [[ $b == '1' || $d == '1' ]]; then if [[ $c == '1' ]]; then _run+=' and ('; fi; fi; for a in ${_prot[@]}; do case $a in tcp) _run+='ip_p=6 or ';; udp) _run+='ip_p=11 or ';; icmp) _run+='ip_p=1 or '; esac; done; if [[ $b == '1' || $d == '1' ]]; then if [[ $c == '1' ]]; then _run=${_run%????}; _run+=')'; fi; elif [[ $b == '1' && $d == '0' && $c == '0' ]]; then _run=${_run%?????}; elif [[ $b == '0' && $d == '1' && $c == '0' ]]; then _run=${_run%?????}; elif [[ $b == '0' && $d == '0' && $c == '1' ]]; then _run=${_run%????}; fi; if [[ $b == '1' || $d == '1' || $c == '1' ]]; then _run+=', '; fi; _run+='accept;"'; else _run+=' -F "0,0,0,0,0"'; fi; if [[ -n $_file ]]; then _run+=' -o /var/log/'$_file; fi; if [[ $_sxl == '1' ]]; then _run+='; fwaccel on'; fi; tput bold; echo -n $_run; tput sgr0; read -sn1; echo; case $REPLY in '') eval $_run;; *) echo 'Abort!'; esac; echo; unset _hosts _ports _prot _file _sxl _run a b c d; fi; fi

SuperTool interactively asks for all data to build up the correct syntax to run fw monitor.

SuperTool adjusts the resulting fw monitor syntax according to the requirements of the gateway it is run.
It identifies if:

• the classic -e syntax (inspect code) is required
• the new -F syntax (simple capture filter) is supported (see Kernel Debug Filters)

It also checks and deactivates SecureXL during fw monitor execution if necessary.
SuperTool is also integrated within our ccc script.

Attention! *Work in progress*

SuperTool will be further improved to support:

• full -F syntax (currently just filters all traffic)
• VSX controls
• decide between AND/OR for hosts
• NOT controls
• SMB appliances

FW Monitor developers: @Coby_Schmidt (LinkedIn), ...
FW Monitor documentation: @Uri_Lewitus (LinkedIn)
FW Monitor memory usage: sk160954

[Vladimir]

@Danny , this is awesome! Happy to see CCC evolution over the past year! I hope that CP will decide one day to officially support or endorse it.

[_Val_]

Wow!

Great job, @Danny 

[Wolfgang]

Danny,

thanks a lot for this, simplifies the daily work.

I used https://tcpdump101.com to built complex fw monitor filter but your tool make this easy.

applause, applause

Wolfgang

[Ziegelsambach]

+1

[Kim_Moberg]

Very nice Danny

but isnt fw monitor changed in r80.20 take 87?

fw monitor -e is changed with filter function isnt?

[HeikoAnkenbrand]

From me 100 points. 👍

I'll add the one-liner to my one-liner list:

One-liner collection

[PhoneBoy]

Wow, great work!

[Tom_Cripps]

Hi @Danny 

I'm having issues with this working? Paste it straight into the CLI or do I need to enter this into a script?

[Danny]

Hi @Tom_Cripps ,

just paste it straight into your Expert mode CLI.

[Tom_Cripps]

Got this working now, just had to press Enter. 

Great work though! Kudos.

[Sven_Glock]

Hi Danny,

nice script! Well done!

I would highly recommend to add a friendly reminder at the end of the script that performing "fwaccel off" can increase the load of the gateway or could lead to outages if the gateways is already well loaded. 

Cheers

Sven

[Danny]

@Sven_Glock ,

that‘s why this SuperTool checks if SecureXL is enabled on versions prior to R80.20 and only disables it while running fw monitor. I checked if disabling SecureXL just for the specified IP addresses (sk194468) would be an option, unluckily this requires adjustments on the SmartCenter, so I had to stay with fwaccel off/on.

[Kane]

Thank you Danny. Awesome work brov.

[Danny]

I'm glad you like it! 🙂

[AkosBakos]

Amazing script.

Now I put this text to my desktop. Maybe should I print it? 🙂

Akos

[Danny]

Go for it and post a photo of your work desk feature the printout! 😎

[FrozT]

This doesn't work at all.  No matter what values I give it it only generates the following command:

Executing ? fw monitor -F "0,0,0,0,0"

I'm using R80.20 - Build 128 in expert mode.  I hate this new syntax for fw monitor.   Can someone tell me how to translate the following from the old fw monitor syntax to the new style?

fw monitor -e "accept (host (1.2.3.4) and net(13.104.0.0,14));"

[Danny]

This is the expected behaviour as -F is currently not supported (see my initial post).
So the tool is working as it should and correctly informs you to use fw monitor with simple filters instead of inspect code.

[JackPrendergast]

Outstanding work Danny. 

My issue with fw monitor has always been its complexity to run a command. Granted, once you have a command written out, its just a case of changing variables - however in the middle of a change, or whilst troubleshooting a situation, getting the syntax completely correct is just a pain for someone like me.

Ill start using fw monitor more proficiently now!

Thank you

[Rick_Carlo]

Holy Cow!  This is AMAZING!!!

[Matthias_Kring]

I need to add an additional ";fi" to get it running. Nevertheless, great helping tool!

[Nicolas_Vanhoek]

 yep,  that fixed it for me too

[abubakr3092]

I tried running the script but it doesn't work. Below is my gateway version.

This is Check Point's software version R80.30 - Build 484
kernel: R80.30 - Build 478

[Danny]

I added ";fi" at the end as this seem to be required now on most systems. Please try again.

[Mike_Jensen]

This tool used to work great for me every time.  I am running R80.30 - Build 217 and no matter what I enter into the tool what shows up to be executed is "fw monitor -T -F "0,0,0,0,0"".  This is true when simply entering a single ip address into the tool and nothing else.

[Danny]

Yes, that's because full -F (simple filter) syntax is not supported yet.

[Mike_Jensen]

Understood.  Do I simply remove the -F from the script to make it work?

[ADe]

I have version R80.40 running, but each IP address is ingored in the filer, result is always : 

fw monitor -T- F "0,0,0,0,0"
What is going wrong, and how can I solve this ?

[Timothy_Hall]

Known limitation.  Quoted from above:

Attention! *Work in progress*

SuperTool will be further improved to support:

• full -F syntax (currently just filters all traffic)

The -F syntax isn't too tough to come up with on your own (-F srcIP,srcPort,dstIP,dstPort,IPProto), but just keep in mind some points mentioned in my Max Capture series:

1. Up to five -F expressions can be utilized with one invocation of fw monitor -F, and the multiple expressions will be ORed together, not ANDed.
2.  Be very careful not to make a syntax error in your -F expression as doing so will give you an unfiltered capture without warning (essentially 0,0,0,0,0) which could impact the performance of the firewall.  Note that wildcards such as "*" and "?" (and even things like "/24") are NOT supported and will be silently treated as a syntax error.
3. A single -F tuple will only show you traffic in one direction (either the c2s or s2c flow), so the equivalent syntax for "host 1.2.3.4" is: fw monitor -F 1.2.3.4,0,0,0,0 -F 0,0,1.2.3.4,0,0
4. Watch out for NATted traffic which can cause packets to "disappear" between certain inspection points after a NAT operation.  Suppose a packet sourced from 192.168.1.50 on our inside network is connecting to Internet IP address 129.82.102.32 on TCP port 443. The source network 192.168.1.0/24 is Hide NATted behind address 63.55.55.1. To match and view the traffic of this connection in both directions, while also taking into consideration the pre-NAT and post-NAT addresses, our fw monitor -F filter would be the following (all on one line):
   fw monitor -F 192.168.1.50,0,129.82.102.32,443,6 -F 63.55.55.1,0,129.82.102.32,443,6 -F 129.82.102.32,443,63.55.55.1,0,6 -F 129.82.102.32,443,192.168.1.50,0,6