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https://github.com/BlackLight/Snort_AIPreproc.git
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Clustering now improved
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BlackLight
parent
5b471d9003
commit
efa5aa1ded
2 changed files with 81 additions and 17 deletions
2
TODO
2
TODO
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@ -2,7 +2,6 @@
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AVERAGE/HIGH PRIORITY:
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======================
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- Dynamic cluster_min_size algorithm
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- Dynamic k parameter in correlation threshold
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- Testing more scenarios, making more hyperalert models
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- Bayesian learning among alerts in alert log
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@ -22,4 +21,5 @@ DONE:
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+ Regex comp cache
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+ Managing hyperalert graph connection inside the alert structure itself
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+ Keeping track of all the streams and alerts even after clustered
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+ Dynamic cluster_min_size algorithm
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96
cluster.c
96
cluster.c
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@ -21,6 +21,7 @@
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#include <stdio.h>
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#include <unistd.h>
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#include <math.h>
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#include <limits.h>
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#include <pthread.h>
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@ -41,6 +42,13 @@ typedef struct {
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UT_hash_handle hh;
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} attribute_value;
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/** Structure containing the count of occurrences of the single alerts in the log */
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typedef struct {
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AI_hyperalert_key key;
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unsigned int count;
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UT_hash_handle hh;
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} AI_alert_occurrence;
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PRIVATE hierarchy_node *h_root[CLUSTER_TYPES] = { NULL };
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PRIVATE AI_config *_config = NULL;
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@ -266,6 +274,8 @@ _AI_merge_alerts ( AI_snort_alert **log )
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{
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if ( tmp != tmp2->next )
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{
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_dpd.logMsg ( "Comparing '%s' and '%s'...\n", tmp->desc, tmp2->next->desc );
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if ( _AI_equal_alarms ( tmp, tmp2->next ))
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{
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if ( !( tmp->grouped_alerts = ( AI_snort_alert** ) realloc ( tmp->grouped_alerts, (++(tmp->grouped_alerts_count)) * sizeof ( AI_snort_alert* ))))
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@ -273,9 +283,9 @@ _AI_merge_alerts ( AI_snort_alert **log )
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tmp->grouped_alerts[ tmp->grouped_alerts_count - 1 ] = tmp2->next;
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count++;
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_dpd.logMsg ( " -> Grouping '%s' and '%s'\n", tmp->desc, tmp2->next->desc );
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tmp3 = tmp2->next->next;
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/* free ( tmp2->next ); */
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tmp2->next = tmp3;
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}
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}
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@ -286,9 +296,67 @@ _AI_merge_alerts ( AI_snort_alert **log )
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}
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}
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_dpd.logMsg ( "\n" );
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return count;
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} /* ----- end of function _AI_merge_alerts ----- */
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/**
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* \brief Get the average heterogeneity coefficient of the set of alerts
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* \return The average heterogeneity coefficient of the set of alerts
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*/
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double
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_AI_get_alerts_heterogeneity ( int *alert_count )
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{
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double heterogeneity = 0.0;
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int distinct_count = 0;
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AI_hyperalert_key key;
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AI_snort_alert *alert_iterator = NULL;
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AI_alert_occurrence *table = NULL,
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*found = NULL;
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*alert_count = 0;
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for ( alert_iterator = alert_log; alert_iterator; alert_iterator = alert_iterator->next )
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{
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found = NULL;
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*alert_count += alert_iterator->grouped_alerts_count;
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key.gid = alert_iterator->gid;
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key.sid = alert_iterator->sid;
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key.rev = alert_iterator->rev;
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HASH_FIND ( hh, table, &key, sizeof ( AI_hyperalert_key ), found );
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if ( !found )
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{
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if ( !( found = (AI_alert_occurrence*) malloc ( sizeof ( AI_alert_occurrence ))))
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_dpd.fatalMsg ( "AIPreproc: Fatal dynamic memory allocation error at %s:%d\n", __FILE__, __LINE__ );
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found->key = key;
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found->count = 1;
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HASH_ADD ( hh, table, key, sizeof ( AI_hyperalert_key ), found );
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} else {
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found->count++;
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}
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}
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for ( found = table; found; found = (AI_alert_occurrence*) found->hh.next )
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distinct_count++;
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if ( *alert_count > 0 )
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heterogeneity = (double) distinct_count / (double) *alert_count;
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else
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heterogeneity = 0.0;
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while ( table )
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{
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found = table;
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HASH_DEL ( table, found );
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free ( found );
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}
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return heterogeneity;
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} /* ----- end of function _AI_get_alerts_heterogeneity ----- */
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/**
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* \brief Print the clustered alerts to a log file
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@ -361,16 +429,17 @@ _AI_cluster_thread ( void* arg )
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hierarchy_node *node, *child;
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cluster_type type;
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cluster_type best_type;
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BOOL has_small_clusters = true;
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FILE *cluster_fp;
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char label[256];
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int hostval;
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int netval;
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int minval;
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int heuristic_val;
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int cluster_min_size = 2;
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int cluster_min_size = 1;
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int alert_count = 0;
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int old_alert_count = 0;
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int single_alerts_count = 0;
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double heterogeneity = 0;
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while ( 1 )
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{
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@ -393,8 +462,6 @@ _AI_cluster_thread ( void* arg )
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continue;
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}
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has_small_clusters = true;
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for ( tmp = alert_log, alert_count=0; tmp; tmp = tmp->next, alert_count++ )
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{
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/* If an alert has an unitialized "grouped alarms count", set its counter to 1 (it only groupes the current alert) */
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@ -403,12 +470,6 @@ _AI_cluster_thread ( void* arg )
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tmp->grouped_alerts_count = 1;
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}
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/* If the current alarm already group at least min_size alarms, then no need to do further clusterization */
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if ( tmp->grouped_alerts_count >= cluster_min_size )
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{
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has_small_clusters = false;
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}
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/* Initialize the clustering hierarchies in the current alert */
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for ( type=0; type < CLUSTER_TYPES; type++ )
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{
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@ -454,8 +515,14 @@ _AI_cluster_thread ( void* arg )
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}
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alert_count -= _AI_merge_alerts ( &alert_log );
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heterogeneity = _AI_get_alerts_heterogeneity( &single_alerts_count );
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/* Get the minimum size for the clusters in function of the heterogeneity of alerts' set */
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if ( heterogeneity > 0 )
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cluster_min_size = (int) round ( 1/heterogeneity );
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else
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cluster_min_size = 1;
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/* while ( has_small_clusters && alert_count > cluster_min_size ) */
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do
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{
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old_alert_count = alert_count;
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@ -488,9 +555,6 @@ _AI_cluster_thread ( void* arg )
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}
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alert_count -= _AI_merge_alerts ( &alert_log );
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/* if ( old_alert_count == alert_count ) */
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/* break; */
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} while ( old_alert_count != alert_count );
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lock_flag = false;
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@ -664,7 +728,7 @@ _AI_copy_clustered_alerts ( AI_snort_alert *node )
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AI_snort_alert*
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AI_get_clustered_alerts ()
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{
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while ( lock_flag );
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for ( ; lock_flag; usleep(100) );
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return _AI_copy_clustered_alerts ( alert_log );
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} /* ----- end of function AI_get_clustered_alerts ----- */
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