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https://issues.apache.org/jira/browse/METRON-686?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15859977#comment-15859977
]
ASF GitHub Bot commented on METRON-686:
---------------------------------------
Github user nickwallen commented on a diff in the pull request:
https://github.com/apache/incubator-metron/pull/438#discussion_r100379863
--- Diff:
metron-platform/metron-enrichment/src/main/java/org/apache/metron/threatintel/triage/ThreatTriageProcessor.java
---
@@ -52,15 +74,36 @@ public ThreatTriageProcessor( SensorEnrichmentConfig
config
@Nullable
@Override
- public Double apply(@Nullable Map input) {
- List<Number> scores = new ArrayList<>();
+ public ThreatScore apply(@Nullable Map input) {
+
+ ThreatScore threatScore = new ThreatScore();
StellarPredicateProcessor predicateProcessor = new
StellarPredicateProcessor();
+ StellarProcessor processor = new StellarProcessor();
VariableResolver resolver = new MapVariableResolver(input,
sensorConfig.getConfiguration(), threatIntelConfig.getConfig());
+
+ // attempt to apply each rule to the threat
for(RiskLevelRule rule : threatTriageConfig.getRiskLevelRules()) {
if(predicateProcessor.parse(rule.getRule(), resolver,
functionResolver, context)) {
- scores.add(rule.getScore());
+
+ // add the rule's score to the overall threat score
+ String reason = execute(rule.getReason(), processor, resolver,
String.class);
+ RuleScore score = new RuleScore(rule, reason);
+ threatScore.addRuleScore(score);
}
}
- return threatTriageConfig.getAggregator().aggregate(scores,
threatTriageConfig.getAggregationConfig());
+
+ // calculate the aggregate threat score
+ Aggregators aggregators = threatTriageConfig.getAggregator();
+ List<Number> allScores =
threatScore.getRuleScores().stream().map(score ->
score.getRule().getScore()).collect(Collectors.toList());
+ Double aggregateScore = aggregators.aggregate(allScores,
threatTriageConfig.getAggregationConfig());
+
+ // return the overall threat score
+ threatScore.setScore(aggregateScore);
+ return threatScore;
+ }
+
+ private <T> T execute(String expression, StellarProcessor processor,
VariableResolver resolver, Class<T> clazz) {
+ Object result = processor.parse(expression, resolver,
functionResolver, context);
--- End diff --
This gets called to execute the 'reason' Stellar expression that is part of
a threat triage rule. It is only called on the rules that are 'fired' (rule
predicate is true) for a particular message (line 89).
A rule's 'reason' is something that could be changed by the user at any
time. I am unsure of a better way to do it. Thoughts?
> Record Rule Set that Fired During Threat Triage
> -----------------------------------------------
>
> Key: METRON-686
> URL: https://issues.apache.org/jira/browse/METRON-686
> Project: Metron
> Issue Type: Improvement
> Reporter: Nick Allen
> Assignee: Nick Allen
>
> h3. Problem
> There is little transparency into the Threat Triage process itself. When
> Threat Triage runs, all I get is a score. I don't know how that score was
> arrived at, which rules were triggered, and the specific values that caused a
> rule to trigger.
> More specifically, there is no way to generate a message that looks like "The
> host 'powned.svr.bank.com' has '230' inbound flows, exceeding the threshold
> of '202'". This makes it difficult for an analyst to action the alert.
> h3. Proposed Solution
> To improve the transparency of the Threat Triage process, I am proposing
> these enhancements.
> (1) Threat Triage should attach to each message all of the rules that fired
> in addition to the total calculated threat triage score.
> (2) Threat Triage should allow a custom message to be generated for each
> rule. The custom message would allow for some form of string interpolation
> so that I can add specific values from each message to the generated alert.
> We could allow this in one or both of the new fields that Casey just added,
> name and comment.
> (3) The specific method of string interpolation will be implemented under a
> separate issue.
> h3. Example
> (1) In this example, we have a telemetry message with a field called 'value'
> that we need to monitor. In Enrichment, I calculate some sort of value
> threshold, over which an alert should be generated.
> (2) In Threat Triage, I use the calculated value threshold to alert on any
> message that has a value exceeding this threshold.
> (3) By leveraging a new field called 'reason', I can embed values from the
> message, like the hostname, value, and value threshold, into the alert
> produced by Threat Triage.
> {code}
> "triageConfig" : {
> "riskLevelRules" : [ {
> "name" : "Abnormal DNS Port",
> "rule" : "source.type == 'bro' and protocol == 'dns' and ip_dst_port
> != 53",
> "score" : 10.0,
> "reason" : "FORMAT('Abnormal DNS Port: expected: 53, found: %s:%d',
> ip_dst_addr, ip_dst_port)"
> } ],
> "aggregator" : "MAX",
> "aggregationConfig" : { }
> }
> {code}
> (4) The Threat Triage process today would add only the total calculated score.
> {code}
> "threat.triage.level": 10.0
> {code}
> With this proposal, Threat Triage would add the following to the message.
> {code}
> "threat.triage.level":{
> "score":10.0,
> "rules":[
> {
> "name":"Abnormal DNS Port",
> "comment":null
> "score":10.0,
> "reason":"Abnormal DNS Port: expected: 53, found: 224.0.0.251:5353",
> }
> ]
> }
> {code}
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