This change adds two new hooks to the Intel framework that can be used
to intercept added and removed indicators and their type.
These hooks are fairly low-level. One immediate use-case is to count the
number of indicators loaded per Intel::Type and enable and disable the
corresponding event groups of the intel/seen scripts.
I attempted to gauge the overhead and while it's definitely there, loading
a file with ~500k DOMAIN entries takes somewhere around ~0.5 seconds hooks
when populated via the min_data_store store mechanism. While that
doesn't sound great, it actually takes the manager on my system 2.5
seconds to serialize and Cluster::publish() the min_data_store alone
and its doing that serially for every active worker. Mostly to say that
the bigger overhead in that area on the manager doing redundant work
per worker.
Co-authored-by: Mohan Dhawan <mohan@corelight.com>
This introduces a new hook into the Intel::seen() function that allows
users to directly interact with the result of a find() call via external
scripts.
This should solve the use-case brought up by @chrisanag1985 in
discussion #3256: Recording and acting on "no intel match found".
@Canon88 was recently asking on Slack about enabling HTTP logging for a
given connection only when an Intel match occurred and found that the
Intel::match() event would only occur on the manager. The
Intel::match_remote() event might be a workaround, but possibly running a
bit too late and also it's just an internal "detail" event that might not
be stable.
Another internal use case revolved around enabling packet recording
based on Intel matches which necessarily needs to happen on the worker
where the match happened. The proposed workaround is similar to the above
using Intel::match_remote().
This hook also provides an opportunity to rate-limit heavy hitter intel
items locally on the worker nodes, or even replacing the event approach
currently used with a customized approach.
This adds a "policy" hook into the logging framework's streams and
filters to replace the existing log filter predicates. The hook
signature is as follows:
hook(rec: any, id: Log::ID, filter: Log::Filter);
The logging manager invokes hooks on each log record. Hooks can veto
log records via a break, and modify them if necessary. Log filters
inherit the stream-level hook, but can override or remove the hook as
needed.
The distribution's existing log streams now come with pre-defined
hooks that users can add handlers to. Their name is standardized as
"log_policy" by convention, with additional suffixes when a module
provides multiple streams. The following adds a handler to the Conn
module's default log policy hook:
hook Conn::log_policy(rec: Conn::Info, id: Log::ID, filter: Log::Filter)
{
if ( some_veto_reason(rec) )
break;
}
By default, this handler will get invoked for any log filter
associated with the Conn::LOG stream.
The existing predicates are deprecated for removal in 4.1 but continue
to work.
* All "Broxygen" usages have been replaced in
code, documentation, filenames, etc.
* Sphinx roles/directives like ":bro:see" are now ":zeek:see"
* The "--broxygen" command-line option is now "--zeexygen"
