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148 lines
4.2 KiB
Text
148 lines
4.2 KiB
Text
##! Activates port-independent protocol detection and selectively disables
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##! analyzers if protocol violations occur.
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module DPD;
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export {
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## Add the DPD logging stream identifier.
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redef enum Log::ID += { LOG };
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## A default logging policy hook for the stream.
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global log_policy: Log::PolicyHook;
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## The record type defining the columns to log in the DPD logging stream.
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type Info: record {
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## Timestamp for when protocol analysis failed.
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ts: time &log;
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## Connection unique ID.
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uid: string &log;
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## Connection ID containing the 4-tuple which identifies endpoints.
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id: conn_id &log;
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## Transport protocol for the violation.
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proto: transport_proto &log;
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## The analyzer that generated the violation.
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analyzer: string &log;
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## The textual reason for the analysis failure.
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failure_reason: string &log;
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};
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## Deprecated, please see https://github.com/zeek/zeek/pull/4200 for details
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option max_violations: table[Analyzer::Tag] of count = table() &deprecated="Remove in v8.1: This has become non-functional in Zeek 7.2, see PR #4200" &default = 5;
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## Analyzers which you don't want to throw
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option ignore_violations: set[Analyzer::Tag] = set();
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## Ignore violations which go this many bytes into the connection.
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## Set to 0 to never ignore protocol violations.
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option ignore_violations_after = 10 * 1024;
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## Add removed services to conn.log, with a - in front of them.
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option track_removed_services_in_connection = F;
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}
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redef record connection += {
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dpd: Info &optional;
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## The set of services (analyzers) for which Zeek has observed a
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## violation after the same service had previously been confirmed.
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service_violation: set[string] &default=set() &ordered;
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};
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event zeek_init() &priority=5
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{
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Log::create_stream(DPD::LOG, [$columns=Info, $path="dpd", $policy=log_policy]);
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}
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event analyzer_confirmation_info(atype: AllAnalyzers::Tag, info: AnalyzerConfirmationInfo) &priority=10
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{
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if ( ! is_protocol_analyzer(atype) && ! is_packet_analyzer(atype) )
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return;
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if ( ! info?$c )
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return;
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local c = info$c;
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local analyzer = Analyzer::name(atype);
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add c$service[analyzer];
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}
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event analyzer_violation_info(atype: AllAnalyzers::Tag, info: AnalyzerViolationInfo) &priority=10
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{
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if ( ! is_protocol_analyzer(atype) && ! is_packet_analyzer(atype) )
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return;
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if ( ! info?$c )
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return;
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local c = info$c;
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local analyzer = Analyzer::name(atype);
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# If the service hasn't been confirmed yet, or already failed,
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# don't generate a log message for the protocol violation.
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if ( analyzer !in c$service || analyzer in c$service_violation )
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return;
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add c$service_violation[analyzer];
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local dpd: Info;
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dpd$ts = network_time();
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dpd$uid = c$uid;
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dpd$id = c$id;
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dpd$proto = get_port_transport_proto(c$id$orig_p);
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dpd$analyzer = analyzer;
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# Encode data into the reason if there's any as done for the old
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# analyzer_violation event, previously.
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local reason = info$reason;
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if ( info?$data )
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{
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local ellipsis = |info$data| > 40 ? "..." : "";
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local data = info$data[0:40];
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reason = fmt("%s [%s%s]", reason, data, ellipsis);
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}
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dpd$failure_reason = reason;
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c$dpd = dpd;
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}
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event analyzer_violation_info(atype: AllAnalyzers::Tag, info: AnalyzerViolationInfo ) &priority=5
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{
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if ( ! is_protocol_analyzer(atype) && ! is_packet_analyzer(atype) )
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return;
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if ( ! info?$c || ! info?$aid )
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return;
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if ( atype in ignore_violations )
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return;
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local c = info$c;
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local aid = info$aid;
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local size = c$orig$size + c$resp$size;
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if ( ignore_violations_after > 0 && size > ignore_violations_after )
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return;
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local disabled = disable_analyzer(c$id, aid, F);
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# add "-service" to the list of services on removal due to violation, if analyzer was confirmed before
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if ( track_removed_services_in_connection && disabled && Analyzer::name(atype) in c$service )
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{
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local rname = cat("-", Analyzer::name(atype));
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if ( rname !in c$service )
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add c$service[rname];
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}
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}
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event analyzer_violation_info(atype: AllAnalyzers::Tag, info: AnalyzerViolationInfo ) &priority=-5
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{
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if ( ! is_protocol_analyzer(atype) && ! is_packet_analyzer(atype) )
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return;
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if ( ! info?$c )
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return;
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if ( info$c?$dpd )
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{
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Log::write(DPD::LOG, info$c$dpd);
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delete info$c$dpd;
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}
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}
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