zeek/scripts/policy/misc/unknown-protocols.zeek

64 lines
2 KiB
Text

##! This script logs information about packet protocols that Zeek doesn't
##! know how to process. Mostly these come from packet analysis plugins when
##! they attempt to forward to the next analyzer, but they also can originate
##! from non-packet analyzers.
@load base/frameworks/notice
module UnknownProtocol;
export {
redef enum Log::ID += { LOG };
global log_policy: Log::PolicyHook;
type Info: record {
## Timestamp for when the measurement occurred.
ts: time &log;
## The string name of the analyzer attempting to forward the protocol.
analyzer: string &log;
## The identifier of the protocol being forwarded.
protocol_id: string &log;
## A certain number of bytes at the start of the unknown protocol's
## header.
first_bytes: string &log;
};
## How many reports for an analyzer/protocol pair will be allowed to
## raise events before becoming rate-limited.
const sampling_threshold : count = 3 &redef;
## The rate-limiting sampling rate. One out of every of this number of
## rate-limited pairs of a given type will be allowed to raise events
## for further script-layer handling. Setting the sampling rate to 0
## will disable all output of rate-limited pairs.
const sampling_rate : count = 100000 &redef;
## How long an analyzer/protocol pair is allowed to keep state/counters in
## in memory. Once the threshold has been hit, this is the amount of time
## before the rate-limiting for a pair expires and is reset.
const sampling_duration = 1hr &redef;
## The number of bytes to extract from the next header and log in the
## first bytes field.
const first_bytes_count = 10 &redef;
}
event unknown_protocol(analyzer_name: string, protocol: count, first_bytes: string)
{
local info : Info;
info$ts = network_time();
info$analyzer = analyzer_name;
info$protocol_id = fmt("0x%x", protocol);
info$first_bytes = bytestring_to_hexstr(first_bytes);
Log::write(LOG, info);
}
event zeek_init() &priority=5
{
Log::create_stream(LOG, [$columns=Info, $path="unknown_protocols", $policy=log_policy]);
}