Snort 2.9.4.1 pkg v.2.5.8
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Anyone still having issues where a blocked IP is removed from snort2c within a few minutes? I'm banging my head here. I've set it for never expire, disabled log limit and removed the 2 cron jobs. They still disappear. I've done a clean install of snort with my old config.. Only 2 options left are to either wipe all snort settings and start fresh or rebuild my box from iso install..
gogol is correct. Anything that causes pfSense to reload the packet filter will automatically dump the table Snort's output plugin uses to implement blocks. Reloads can happen because of edits within the GUI, DHCP address changes, links going up and down, etc. Look for the tag check_reload_status: Syncing firewall in the system log. That's an event that clears the table, I believe.
Not really sure why this is a big deal to folks, though. If an offending packet for that IP traverses the firewall again, the IP will be "re-blocked". Or put another way, if whatever caused it to get blocked in the first place repeats, then it will be blocked again. Maybe I'm missing something?
Bill
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I've been away for a couple of weeks and when I brought it up last month, there wasnt a reason why. Going thru my cron jobs, there is a job that re-sync every 15 minutes so that would explain why the table is being cleared..
This is new behavior for snort. I've been using snort on pfsense for many years and it never acted this way. And if it did, I've never noticed it while testing for last 2 developers of the snort package. This is why I bring it up.
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I've been away for a couple of weeks and when I brought it up last month, there wasnt a reason why. Going thru my cron jobs, there is a job that re-sync every 15 minutes so that would explain why the table is being cleared..
This is new behavior for snort. I've been using snort on pfsense for many years and it never acted this way. And if it did, I've never noticed it while testing for last 2 developers of the snort package. This is why I bring it up.
Snort really has nothing at all to do with clearing the snort2c table. Perhaps pfSense made some changes to the expiretable script? All the Snort package does is create a cron task that executes every 5 minutes. That tasks looks for snort2c entries that have had no activity for the last period specified in the "Clear Blocks Interval" on the If Settings tab. Entries matching that are removed. You can see the content of the cron task in /etc/crontab. Here is the line:
*/5 * * * * root /usr/bin/nice -n20 /usr/local/sbin/expiretable -t 3600 snort2cI have mine set for 1 hour, hence the 3600 seconds value. The expiretable script is used to clear a number of other tables as well and is not proprietary to Snort. I have not noticed any premature clearing of entries on my system, but Snort is the only package I run. Perhaps something else loaded on your firewall is triggering the reloading of the packet filter and thus dumping the snort2c table?
Bill
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I figured out what was clearing it. My rules would reload every 15 minutes because of schedule fw rule I have (pfsense creates this cron if you have schedule fw rules). I've had this rule for a while.. Either I haven't noticed it clearing out snort2c or like you said, something change with the expiretable script itself on 2.1. What I dont understand, if you set it for never; a simple reload of the rules will wipe it out. I'll have to dig deeper on why this is because I would think other tables would get wiped out then.
Thank you again for all your work you have done on this package.. Its come a long way
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I figured out what was clearing it. My rules would reload every 15 minutes because of schedule fw rule I have (pfsense creates this cron if you have schedule fw rules). I've had this rule for a while.. Either I haven't noticed it clearing out snort2c or like you said, something change with the expiretable script itself on 2.1. What I dont understand, if you set it for never; a simple reload of the rules will wipe it out. I'll have to dig deeper on why this is because I would think other tables would get wiped out then.
Thank you again for all your work you have done on this package.. Its come a long way
The key is that it's not Snort that really does the blocking/unblocking of an IP. Not directly, anyway. A third-party plug-in called Spoink is compiled into Snort as an output plugin. This plugin inserts itself into the Alert chain in Snort so that it gets a copy of every alert. It then compares the IP addresses in the alert to the Whitelist, and if there is no match based on the SRC/DST/BOTH logic it uses pfctl to insert the IP into the packet filter engine. At that point any part of Snort is done with the block.
I suspect what happens is the reload of the firewall rules on the scheduled task is wiping the block table. That is logical, because on the assumption a new set of rules are coming into play, you would not want old blocks leftover in the block table. In this scenario, Snort's snort2c table is essentially "collateral damage" as they say… :D
Bill
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So funny thing happend, from what i can make out from the logs. Snort rules updated last night. After that it ran the snortstart and it stopped running. Nothing in the logs showed me why it wasnt working but i typed snort into the command line and its giving me a
"/libexec/ld-elf.so.1" shared object "libpcap.so.1" not found, required by snort." So i can only assume the shared object ran off some where :P and no i didn't delete it
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Another question from me , is it normal , both lan and wan snort interface is not running after server restart (auto restart using cron). Need to click on the enable button again to make it run.
If yes , perhaps , Bmeeks can add to wish list , to auto enable the interface , as some server (low spec) will need to be auto restart from time to time using cron.
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So funny thing happend, from what i can make out from the logs. Snort rules updated last night. After that it ran the snortstart and it stopped running. Nothing in the logs showed me why it wasnt working but i typed snort into the command line and its giving me a
"/libexec/ld-elf.so.1" shared object "libpcap.so.1" not found, required by snort." So i can only assume the shared object ran off some where :P and no i didn't delete it
To continue my story, i found out what deleted it. bandwidthd was maxing out my cpu the other day so i figured i remove it. When i uninstalled it, it took the libpcap file with it too, i reinstalled bandwidthd but left it disabled and snort is running fine again
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So funny thing happend, from what i can make out from the logs. Snort rules updated last night. After that it ran the snortstart and it stopped running. Nothing in the logs showed me why it wasnt working but i typed snort into the command line and its giving me a
"/libexec/ld-elf.so.1" shared object "libpcap.so.1" not found, required by snort." So i can only assume the shared object ran off some where :P and no i didn't delete it
To continue my story, i found out what deleted it. bandwidthd was maxing out my cpu the other day so i figured i remove it. When i uninstalled it, it took the libpcap file with it too, i reinstalled bandwidthd but left it disabled and snort is running fine again
The new PBI package management system in 2.1 eliminates these issues. Each package has the equivalent of its own chroot jail, so to speak, where its executables and libraries go.
Bill
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Not trying to get the thread off topic, but just FYI.
I have submitted the Pull Requests to the Core Developer Team for updating the Snort package to 2.9.4.6 pkg version 2.5.9. This will update the Snort binary to the current 2.9.4.6 code. The 2.5.9 GUI package update fixes a couple of bugs and introduces Host Attribute Table support along with configurable rule update start times (an often asked for feature).
The full details can be seen here for the GUI: https://github.com/pfsense/pfsense-packages/pull/461 and here for the binary: https://github.com/pfsense/pfsense-tools/pull/122
I will start a new thread on this version when it is approved and posted.
Bill
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Thanks Bill!!!
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yay updates, I look forward to all the updated features.
I have a question, i see the version that snort is using for libpcap,pcre,zlib versions aren't the newest. Is there any benefits to compiling them with the newest ones? Was just curious thank you
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yay updates, I look forward to all the updated features.
I have a question, i see the version that snort is using for libpcap,pcre,zlib versions aren't the newest. Is there any benefits to compiling them with the newest ones? Was just curious thank you
On the 2.0.x platform Snort has to work as harmoniously as possible and utilize the libraries shared with other packages. On the 2.1 platform with PBI, that's not an issue. So for now, with the Snort package supported on both 2.0.x and 2.1, the slightly older libraries are used. Once everything is just 2.1 with PBI, then each package can use its own library versions.
In my testing with 2.9.4.6 I've seen no issues with the current library versions.
Bill
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yay updates, I look forward to all the updated features.
I have a question, i see the version that snort is using for libpcap,pcre,zlib versions aren't the newest. Is there any benefits to compiling them with the newest ones? Was just curious thank you
On the 2.0.x platform Snort has to work as harmoniously as possible and utilize the libraries shared with other packages. On the 2.1 platform with PBI, that's not an issue. So for now, with the Snort package supported on both 2.0.x and 2.1, the slightly older libraries are used. Once everything is just 2.1 with PBI, then each package can use its own library versions.
In my testing with 2.9.4.6 I've seen no issues with the current library versions.
Bill
makes sense. Thank you
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Not trying to get the thread off topic, but just FYI.
I have submitted the Pull Requests to the Core Developer Team for updating the Snort package to 2.9.4.6 pkg version 2.5.9. This will update the Snort binary to the current 2.9.4.6 code. The 2.5.9 GUI package update fixes a couple of bugs and introduces Host Attribute Table support along with configurable rule update start times (an often asked for feature).
The full details can be seen here for the GUI: https://github.com/pfsense/pfsense-packages/pull/461 and here for the binary: https://github.com/pfsense/pfsense-tools/pull/122
I will start a new thread on this version when it is approved and posted.
Bill
Glad to hear this
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Apparently Shinzo allready posted the update and the Core team has pushed the update.
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Apparently Shinzo allready posted the update and the Core team has pushed the update.
Yes, they were very fast to approve and push. Haven't had time yet to create the Change Log (thanks to Shinzo for doing this for me!) and post some screenshots of the changes.
Bill
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A third-party plug-in called Spoink
This is probably a silly question, but searching hasn't (yet) found me a definitive answer - are alerts automatically blocked by the Spoink / pf mechanism even if no blocking is turned on in snort's gui ?
Thanks..
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A third-party plug-in called Spoink
This is probably a silly question, but searching hasn't (yet) found me a definitive answer - are alerts automatically blocked by the Spoink / pf mechanism even if no blocking is turned on in snort's gui ?
Thanks..
No, if "Block Offenders" is not checked on the If Settings tab for the interface in the Snort GUI, no blocking will occur. You will see Alerts, but remember that in the pfSense implementation an "alert" does not automatically equate to a "block". Alerts are simply read from the log and displayed to show a detected event that matched a rule. The Spoink plugin also sees these "alerts" and compares the IP addresses in them to its Whitelist of "never block IP addresses". If blocking is enabled for the interface, and the IP is not in the Whitelist, then the IP is added to the block table in the firewall.
Bill
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Thanks Bill, that explains things perfectly.
Another question if I may - if I'm running snort on the WAN interface, I should choose DST rather than SRC in the block offenders option, yes?
(I think last time I did this, I chose SRC, which caused all internet traffic incoming to the WAN interface to be blocked :-[ )
