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Snort_AIPreproc
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Output database support (for MySQL) now complete

This commit is contained in:
BlackLight 2010-10-02 17:46:15 +02:00
parent f28830d744
commit 7bbcb865af
8 changed files with 397 additions and 61 deletions
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69
README
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@ -158,7 +158,8 @@ preprocessor ai: \
correlation_rules_dir "/your/snort/dir/etc/corr_rules" \
correlated_alerts_dir "/your/snort/dir/log/correlated_alerts" \
correlation_threshold_coefficient 0.5 \
database ( type="mysql", name="snort", user="snortusr", password="snortpass", host="dbhost" ) \
database ( type="dbtype", name="snort", user="snortusr", password="snortpass", host="dbhost" ) \
output_database ( type="dbtype", name="snort", user="snortusr", password="snortpass", host="dbhost" ) \
database_parsing_interval 30 \
cluster_max_alert_interval 14400 \
clusterfile "/your/snort/dir/log/clustered_alerts" \
@ -173,36 +174,33 @@ preprocessor ai: \
The options are the following:
- hashtable_cleanup_interval: The interval that should occur from the cleanup of
the hashtable of TCP streams and the next one (default if not specified: 300
seconds)
- tcp_stream_expire_interval: The interval that should occur for marking a TCP
stream as "expired", if no more packets are received inside of that and it's not
"marked" as suspicious (default if not specified: 300 seconds)
- alertfile: The file where Snort saves its alerts, if they are saved to a file
and not to a database (default if not specified: /var/log/snort/alert)
- alert_history_file: The file keeping track of the history, in binary format,
of all the alerts received by the IDS, so that the module can build some
statistical correlation inferences over the past
- alert_serialization_interval: The interval that should occur from a
serialization of a buffer of alerts on the history file and the next one
(default if not specified: 1 hour, as it is a quite expensive operation in terms
of resources if the system received many alerts)
- alert_bufsize: Size of the buffer containing the alerts to be sent, in group,
to the serializer thread. The buffer is sent when full and made empty even
when the alert_serialization_interval parameter is not expired yet, for
avoiding overflows, other memory problems or deadlocks (default value if
not specified: 30)
- alert_clustering_interval: The interval that should occur from the clustering
of the alerts in the log according to the provided clustering hierarchies and
the next one (default if not specified: 300 seconds)
- bayesian_correlation_interval: Interval, in seconds, that should occur between
two alerts in the history for considering them as, more or less strongly,
correlated (default: 1200 seconds). NOTE: A value of 0 will disable the bayesian
@ -210,23 +208,28 @@ correlation. This setting is strongly suggested when your alert log is still
"learning", i.e. when you don't have enough alerts yet. After this period, you
can set the correlation interval to any value.
- bayesian_correlation_cache_validity: interval, in seconds, for which an entry
in the bayesian correlation hash table (i.e. a pair of alerts with the
associated historical bayesian correlation) is considered as valid
before being updated (default: 600 seconds)
- correlation_graph_interval: The interval that should occur from the building
of the correlation graph between the clustered alerts and the next one (default
if not specified: 300 seconds)
- correlation_rules_dir: Directory where the correlation rules are saved, as XML
files (default if not specified: /etc/snort/corr_rules)
- correlated_alerts_dir: Directory where the information between correlated
alerts will be saved, as .dot files ready to be rendered as graphs and, if
libgraphviz support is enabled, as .png and .ps files as well (default if not
specified: /var/log/snort/clustered_alerts)
- correlation_threshold_coefficient: The threshold the software uses for stating
two alerts are correlated is avg(correlation coefficient) + k *
std_deviation(correlation_coefficient). The value of k is specified through this
@ -239,26 +242,17 @@ where no correlation exists). When the value of k raises also the threshold for
two alerts for being considered as correlated raises. A high value of k may just
lead to an empty correlation graph
- database: If Snort saves its alerts to a database and the module was compiled
with database support (e.g. --with-mysql) this option specifies the
information for accessing that database. The fields in side are
-- type: DBMS to be used (so far MySQL and PostgreSQL are supported)
-- name: Database name
-- user: Username for accessing the database
-- password: Password for accessing the database
-- host: Host holding the database
- database_parsing_interval: The interval that should occur between a read of
the alerts from database and the next one (default if not specified: 30 seconds)
- clusterfile: File where the clustered alerts will be saved by the module
(default if not specified: /var/log/snort/clustered_alerts)
- cluster_max_alert_interval: Maximum time interval, in seconds, occurred
between two alerts for considering them as part of the same cluster (default:
14400 seconds, i.e. 4 hours). Specify 0 for this option if you want to
cluster alerts regardlessly of how much time occurred between them
- cluster: Clustering hierarchy or list of hierarchies to be applied for
grouping similar alerts. This option needs to specify:
-- class: Class of the cluster node. It may be src_addr, dst_addr, src_port
@ -269,6 +263,41 @@ grouping similar alerts. This option needs to specify:
range (specified as xxx-xxx)
- database: If Snort saves its alerts to a database and the module was compiled
with database support (e.g. --with-mysql) this option specifies the
information for accessing that database. The fields in side are
-- type: DBMS to be used (so far MySQL and PostgreSQL are supported)
-- name: Database name
-- user: Username for accessing the database
-- password: Password for accessing the database
-- host: Host holding the database
- database_parsing_interval: The interval that should occur between a read of
the alerts from database and the next one (default if not specified: 30 seconds)
- hashtable_cleanup_interval: The interval that should occur from the cleanup of
the hashtable of TCP streams and the next one (default if not specified: 300
seconds)
- output_database: Specify this option if you want to save the outputs from the
module (correlated alerts, clustered alerts, alerts information and their
associated packets streams, and so on) to a relational database as
well (by default the module only saves the alerts on static plain files). The
options here are the same specified for the 'database' option.
The structure of this database can be seen in the files schemas/*.sql (replace
to * the name of your DBMS). If you want to initialize the tables needed by the
module, just give the right file to your database, e.g. for MySQL
$ mysql -uusername -ppassword dbname < schemas/mysql.sql
- tcp_stream_expire_interval: The interval that should occur for marking a TCP
stream as "expired", if no more packets are received inside of that and it's not
"marked" as suspicious (default if not specified: 300 seconds)
====================
5. Correlation rules
====================

5
TODO
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@ -2,7 +2,9 @@
AVERAGE/HIGH PRIORITY:
======================
- Save clusters and correlations to db
- Full PostgreSQL support for output db
- Redefine function names
- Errno
- Web interface
- Code profiling
- Comment all the code!!!
@ -31,4 +33,5 @@ DONE:
+ Bayesian learning among alerts in alert log
+ Split bayesian correlation out of correlation.c
+ Clustering alerts with time constraints
+ Save clusters and correlations to db

26
cluster.c
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@ -23,6 +23,7 @@
#include <unistd.h>
#include <math.h>
#include <limits.h>
#include <errno.h>
#include <pthread.h>
/** \defgroup cluster Manage the clustering of alarms
@ -262,6 +263,8 @@ PRIVATE int
_AI_merge_alerts ( AI_snort_alert **log )
{
AI_snort_alert *tmp, *tmp2, *tmp3;
AI_alerts_couple *alerts_couple;
pthread_t db_thread;
int count = 0;
for ( tmp = *log; tmp; tmp = tmp->next )
@ -279,6 +282,27 @@ _AI_merge_alerts ( AI_snort_alert **log )
/* If the two alerts are equal... */
if ( _AI_equal_alerts ( tmp, tmp2->next ))
{
/* If we are storing the outputs of the module to a database, save the cluster containing the two alerts */
if ( config->outdbtype != outdb_none )
{
if ( !( alerts_couple = (AI_alerts_couple*) malloc ( sizeof ( AI_alerts_couple ))))
_dpd.fatalMsg ( "AIPreproc: Fatal dynamic memory allocation error at %s:%d\n", __FILE__, __LINE__ );
alerts_couple->alert1 = tmp;
alerts_couple->alert2 = tmp2->next;
if ( pthread_create ( &db_thread, NULL, AI_store_cluster_to_db_thread, alerts_couple ) != 0 )
{
_dpd.fatalMsg ( "AIPreproc: Failed to create the cluster-to-database thread: %s\n", strerror(errno) );
}
if ( pthread_join ( db_thread, NULL ) != 0 )
{
_dpd.fatalMsg ( "AIPreproc: Could not join the cluster-to-database thread: %s\n", strerror(errno) );
}
}
/* Merge the two alerts */
if ( !( tmp->grouped_alerts = ( AI_snort_alert** ) realloc ( tmp->grouped_alerts, (++(tmp->grouped_alerts_count)) * sizeof ( AI_snort_alert* ))))
_dpd.fatalMsg ( "AIPreproc: Fatal dynamic memory allocation error at %s:%d\n", __FILE__, __LINE__ );
@ -685,7 +709,7 @@ AI_hierarchies_build ( hierarchy_node **nodes, int n_nodes )
if ( pthread_create ( &cluster_thread, NULL, _AI_cluster_thread, NULL ) != 0 )
{
_dpd.fatalMsg ( "Failed to create the hash cleanup thread\n" );
_dpd.fatalMsg ( "AIPreproc: Failed to create the hash cleanup thread\n" );
}
} /* ----- end of function AI_hierarchies_build ----- */

40
correlation.c
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@ -25,6 +25,7 @@
#include <unistd.h>
#include <time.h>
#include <math.h>
#include <errno.h>
#include <alloca.h>
#include <sys/stat.h>
#include <pthread.h>
@ -44,35 +45,11 @@
/** Enumeration for the types of XML tags */
enum { inHyperAlert, inSnortIdTag, inPreTag, inPostTag, TAG_NUM };
/** Key for the correlation hash table */
typedef struct {
/** First alert */
AI_snort_alert *a;
/** Second alert */
AI_snort_alert *b;
} AI_alert_correlation_key;
/** Struct representing the correlation between all the couples of alerts */
typedef struct {
/** Hash key */
AI_alert_correlation_key key;
/** Correlation coefficient */
double correlation;
/** Make the struct 'hashable' */
UT_hash_handle hh;
} AI_alert_correlation;
PRIVATE AI_hyperalert_info *hyperalerts = NULL;
PRIVATE AI_snort_alert *alerts = NULL;
PRIVATE AI_alert_correlation *correlation_table = NULL;
PRIVATE pthread_mutex_t mutex;
/**
* \brief Clean up the correlation hash table
*/
@ -706,6 +683,8 @@ AI_alert_correlation_thread ( void *arg )
AI_snort_alert *alert_iterator = NULL,
*alert_iterator2 = NULL;
pthread_t db_thread;
#ifdef HAVE_LIBGVC
char corr_png_file[4096] = { 0 };
GVC_t *gvc = NULL;
@ -873,6 +852,19 @@ AI_alert_correlation_thread ( void *arg )
corr->key.a->derived_alerts[ corr->key.a->n_derived_alerts - 1 ] = corr->key.b;
corr->key.b->parent_alerts [ corr->key.b->n_parent_alerts - 1 ] = corr->key.a;
_AI_print_correlated_alerts ( corr, fp );
if ( config->outdbtype != outdb_none )
{
if ( pthread_create ( &db_thread, NULL, AI_store_correlation_to_db_thread, corr ) != 0 )
{
_dpd.fatalMsg ( "AIPreproc: Failed to create the correlation-to-database storing thread: %s\n", strerror ( errno ));
}
if ( pthread_join ( db_thread, NULL ) != 0 )
{
_dpd.fatalMsg ( "AIPreproc: Failed to join the correlation-to-database storing thread: %s\n", strerror ( errno ));
}
}
}
}

274
outdb.c
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@ -27,17 +27,40 @@
#ifdef HAVE_DB
#include "db.h"
#include "uthash.h"
#include <alloca.h>
#include <pthread.h>
/** Enumeration for describing the table in the output database */
enum { ALERTS_TABLE, IPV4_HEADERS_TABLE, TCP_HEADERS_TABLE, PACKET_STREAMS_TABLE, CLUSTERED_ALERTS_TABLE, CORRELATED_ALERTS_TABLE, N_TABLES };
/** Tables in the output database */
static const char *outdb_config[] = {
"ca_alerts", "ca_ipv4_headers", "ca_tcp_headers",
"ca_packet_streams", "ca_clustered_alerts", "ca_correlated_alerts"
};
/** Hash table built as cache for the couple of alerts already belonging to the same cluster,
* for avoiding more queries on the database*/
typedef struct {
AI_alerts_couple *alerts_couple;
unsigned long cluster_id;
UT_hash_handle hh;
} AI_couples_cache;
/** Mutex object, for managing concurrent thread access to the database */
PRIVATE pthread_mutex_t mutex;
PRIVATE AI_couples_cache *couples_cache = NULL;
/**
* \brief Initialize the mutex on the output database
*/
void
AI_outdb_mutex_initialize ()
{
pthread_mutex_init ( &mutex, NULL );
} /* ----- end of function AI_outdb_mutex_initialize ----- */
/**
* \brief Thread for storing an alert to the database
@ -47,8 +70,10 @@ PRIVATE pthread_mutex_t mutex;
void*
AI_store_alert_to_db_thread ( void *arg )
{
char srcip[INET_ADDRSTRLEN], dstip[INET_ADDRSTRLEN];
char query[65535] = { 0 };
char srcip[INET_ADDRSTRLEN],
dstip[INET_ADDRSTRLEN];
unsigned char *pkt_data = NULL;
unsigned long latest_ip_hdr_id = 0,
latest_tcp_hdr_id = 0,
@ -61,13 +86,11 @@ AI_store_alert_to_db_thread ( void *arg )
DB_row row;
AI_snort_alert *alert = (AI_snort_alert*) arg;
pthread_mutex_init ( &mutex, NULL );
pthread_mutex_lock ( &mutex );
if ( !DB_out_init() )
_dpd.fatalMsg ( "AIPreproc: Unable to connect to output database '%s'\n", config->outdbname );
pthread_mutex_lock ( &mutex );
inet_ntop ( AF_INET, &(alert->ip_src_addr), srcip, INET_ADDRSTRLEN );
inet_ntop ( AF_INET, &(alert->ip_dst_addr), dstip, INET_ADDRSTRLEN );
@ -84,7 +107,7 @@ AI_store_alert_to_db_thread ( void *arg )
srcip,
dstip );
DB_out_query ( query );
DB_free_result ((DB_result) DB_out_query ( query ));
memset ( query, 0, sizeof ( query ));
snprintf ( query, sizeof ( query ), "SELECT MAX(ip_hdr_id) FROM %s", outdb_config[IPV4_HEADERS_TABLE] );
@ -92,11 +115,13 @@ AI_store_alert_to_db_thread ( void *arg )
if ( !( res = (DB_result) DB_out_query ( query )))
{
_dpd.logMsg ( "AIPreproc: Warning: error in executing query: '%s'\n", query );
pthread_mutex_unlock ( &mutex );
pthread_exit ((void*) 0);
}
if ( !( row = (DB_row) DB_fetch_row ( res )))
{
pthread_mutex_unlock ( &mutex );
pthread_exit ((void*) 0);
}
@ -118,7 +143,7 @@ AI_store_alert_to_db_thread ( void *arg )
ntohs (alert->tcp_window ),
ntohs (alert->tcp_len ));
DB_out_query ( query );
DB_free_result ((DB_result) DB_out_query ( query ));
memset ( query, 0, sizeof ( query ));
snprintf ( query, sizeof ( query ), "SELECT MAX(tcp_hdr_id) FROM %s", outdb_config[TCP_HEADERS_TABLE] );
@ -126,11 +151,13 @@ AI_store_alert_to_db_thread ( void *arg )
if ( !( res = (DB_result) DB_out_query ( query )))
{
_dpd.logMsg ( "AIPreproc: Warning: error in executing query: '%s'\n", query );
pthread_mutex_unlock ( &mutex );
pthread_exit ((void*) 0);
}
if ( !( row = (DB_row) DB_fetch_row ( res )))
{
pthread_mutex_unlock ( &mutex );
pthread_exit ((void*) 0);
}
@ -152,7 +179,7 @@ AI_store_alert_to_db_thread ( void *arg )
latest_ip_hdr_id,
((alert->ip_proto == IPPROTO_TCP || alert->ip_proto == IPPROTO_UDP) ? latest_tcp_hdr_id : 0));
DB_out_query ( query );
DB_free_result ((DB_result) DB_out_query ( query ));
memset ( query, 0, sizeof ( query ));
snprintf ( query, sizeof ( query ), "SELECT MAX(alert_id) FROM %s", outdb_config[ALERTS_TABLE] );
@ -160,11 +187,13 @@ AI_store_alert_to_db_thread ( void *arg )
if ( !( res = (DB_result) DB_out_query ( query )))
{
_dpd.logMsg ( "AIPreproc: Warning: error in executing query: '%s'\n", query );
pthread_mutex_unlock ( &mutex );
pthread_exit ((void*) 0);
}
if ( !( row = (DB_row) DB_fetch_row ( res )))
{
pthread_mutex_unlock ( &mutex );
pthread_exit ((void*) 0);
}
@ -196,14 +225,241 @@ AI_store_alert_to_db_thread ( void *arg )
pkt->timestamp,
pkt_data );
DB_out_query ( query );
DB_free_result ((DB_result) DB_out_query ( query ));
}
}
pthread_mutex_unlock ( &mutex );
pthread_exit ((void*) 0);
return (void*) 0;
}
} /* ----- end of function AI_store_alert_to_db_thread ----- */
/**
* \brief Store an alert cluster to database
* \param arg Struct pointer containing the couple of alerts to be clustered together
*/
void*
AI_store_cluster_to_db_thread ( void *arg )
{
unsigned long cluster1 = 0,
cluster2 = 0,
latest_cluster_id = 0;
char query[1024] = { 0 },
srcip[INET_ADDRSTRLEN] = { 0 },
dstip[INET_ADDRSTRLEN] = { 0 },
srcport[10] = { 0 },
dstport[10] = { 0 };
AI_alerts_couple *alerts_couple = (AI_alerts_couple*) arg;
AI_couples_cache *found = NULL;
DB_result res;
DB_row row;
BOOL new_cluster = false;
pthread_mutex_lock ( &mutex );
/* Check if the couple of alerts is already in our cache, so it already
* belongs to the same cluster. If so, just return */
HASH_FIND ( hh, couples_cache, alerts_couple, sizeof ( AI_alerts_couple ), found );
if ( found )
{
pthread_mutex_unlock ( &mutex );
pthread_exit ((void*) 0);
return (void*) 0;
}
/* Initialize the database (it just does nothing if it is already initialized) */
if ( !DB_out_init() )
_dpd.fatalMsg ( "AIPreproc: Unable to connect to output database '%s'\n", config->outdbname );
/* If one of the two alerts has no alert_id, simply return */
if ( !alerts_couple->alert1->alert_id || !alerts_couple->alert2->alert_id )
{
pthread_mutex_unlock ( &mutex );
pthread_exit ((void*) 0);
return (void*) 0;
}
/* Check if there already exist a cluster containing one of them */
memset ( query, 0, sizeof ( query ));
snprintf ( query, sizeof ( query ),
"SELECT cluster_id FROM %s WHERE alert_id=%lu OR alert_id=%lu",
outdb_config[ALERTS_TABLE], alerts_couple->alert1->alert_id, alerts_couple->alert2->alert_id );
if ( !( res = (DB_result) DB_out_query ( query )))
{
_dpd.logMsg ( "AIPreproc: Warning: error in executing query: '%s'\n", query );
pthread_mutex_unlock ( &mutex );
pthread_exit ((void*) 0);
return (void*) 0;
}
if ( !( row = (DB_row) DB_fetch_row ( res )))
{
pthread_mutex_unlock ( &mutex );
pthread_exit ((void*) 0);
return (void*) 0;
}
/* If no cluster exists containing at least of them, create it */
new_cluster = false;
if ( !row[0] && !row[1] )
{
new_cluster = true;
} else {
if ( row[0] )
{
cluster1 = strtoul ( row[0], NULL, 10 );
}
if ( row[1] )
{
cluster2 = strtoul ( row[1], NULL, 10 );
}
if ( cluster1 == 0 && cluster2 == 0 )
{
new_cluster = true;
}
}
DB_free_result ( res );
/* If both the alerts already belong to the same cluster (but they're not in the cache yet),
* insert them in the cache */
if ( cluster1 != 0 && cluster2 != 0 && cluster1 == cluster2 )
{
if ( !( found = ( AI_couples_cache* ) malloc ( sizeof ( AI_couples_cache ))))
_dpd.fatalMsg ( "AIPreproc: Fatal dynamic allocation memory at %s:%d\n", __FILE__, __LINE__ );
found->alerts_couple = alerts_couple;
found->cluster_id = cluster1;
HASH_ADD ( hh, couples_cache, alerts_couple, sizeof ( AI_alerts_couple ), found );
pthread_mutex_unlock ( &mutex );
pthread_exit ((void*) 0);
return (void*) 0;
}
if ( new_cluster )
{
/* Insert a new cluster containing alert1 and alert2 for now */
inet_ntop ( AF_INET, &(alerts_couple->alert1->ip_src_addr), srcip, INET_ADDRSTRLEN );
inet_ntop ( AF_INET, &(alerts_couple->alert1->ip_dst_addr), dstip, INET_ADDRSTRLEN );
snprintf ( srcport, sizeof ( srcport ), "%u", ntohs( alerts_couple->alert1->tcp_src_port ));
snprintf ( dstport, sizeof ( dstport ), "%u", ntohs( alerts_couple->alert1->tcp_dst_port ));
memset ( query, 0, sizeof ( query ));
snprintf ( query, sizeof ( query ),
"INSERT INTO %s ( clustered_srcip, clustered_dstip, clustered_srcport, clustered_dstport ) "
"VALUES ( '%s', '%s', '%s', '%s' )",
outdb_config[CLUSTERED_ALERTS_TABLE],
((alerts_couple->alert1->h_node[src_addr]) ? alerts_couple->alert1->h_node[src_addr]->label : srcip),
((alerts_couple->alert1->h_node[dst_addr]) ? alerts_couple->alert1->h_node[dst_addr]->label : dstip),
((alerts_couple->alert1->h_node[src_port]) ? alerts_couple->alert1->h_node[src_port]->label : srcport),
((alerts_couple->alert1->h_node[dst_port]) ? alerts_couple->alert1->h_node[dst_port]->label : dstport)
);
DB_free_result ((DB_result) DB_out_query ( query ));
memset ( query, 0, sizeof ( query ));
snprintf ( query, sizeof ( query ),
"SELECT MAX(cluster_id) FROM %s", outdb_config[CLUSTERED_ALERTS_TABLE] );
if ( !( res = (DB_result) DB_out_query ( query )))
{
_dpd.logMsg ( "AIPreproc: Warning: error in executing query: '%s'\n", query );
pthread_mutex_unlock ( &mutex );
pthread_exit ((void*) 0);
return (void*) 0;
}
if ( !( row = (DB_row) DB_fetch_row ( res )))
{
pthread_mutex_unlock ( &mutex );
pthread_exit ((void*) 0);
return (void*) 0;
}
latest_cluster_id = strtoul ( row[0], NULL, 10 );
DB_free_result ( res );
/* Update the two alerts, setting them as belonging to the new cluster */
memset ( query, 0, sizeof ( query ));
snprintf ( query, sizeof ( query ),
"UPDATE %s SET cluster_id=%lu WHERE alert_id=%lu OR alert_id=%lu",
outdb_config[ALERTS_TABLE], latest_cluster_id,
alerts_couple->alert1->alert_id, alerts_couple->alert2->alert_id );
DB_free_result ((DB_result) DB_out_query ( query ));
} else {
/* Update the alert marked as 'not clustered' */
if ( !cluster1 )
{
memset ( query, 0, sizeof ( query ));
snprintf ( query, sizeof ( query ),
"UPDATE %s SET cluster_id=%lu WHERE alert_id=%lu",
outdb_config[ALERTS_TABLE], cluster2, alerts_couple->alert1->alert_id );
DB_free_result ((DB_result) DB_out_query ( query ));
} else {
memset ( query, 0, sizeof ( query ));
snprintf ( query, sizeof ( query ),
"UPDATE %s SET cluster_id=%lu WHERE alert_id=%lu",
outdb_config[ALERTS_TABLE], cluster1, alerts_couple->alert2->alert_id );
DB_free_result ((DB_result) DB_out_query ( query ));
}
}
/* Add the couple to the cache */
if ( !( found = ( AI_couples_cache* ) malloc ( sizeof ( AI_couples_cache ))))
_dpd.fatalMsg ( "AIPreproc: Fatal dynamic allocation memory at %s:%d\n", __FILE__, __LINE__ );
found->alerts_couple = alerts_couple;
found->cluster_id = cluster1;
HASH_ADD ( hh, couples_cache, alerts_couple, sizeof ( AI_alerts_couple ), found );
pthread_mutex_unlock ( &mutex );
pthread_exit ((void*) 0);
return (void*) 0;
} /* ----- end of function AI_store_cluster_to_db_thread ----- */
/**
* \brief Store the correlation between two alerts to the output database
* \param arg Structure containing the two alerts to be saved and their correlation
*/
void*
AI_store_correlation_to_db_thread ( void *arg )
{
char query[1024] = { 0 };
AI_alert_correlation *corr = (AI_alert_correlation*) arg;
pthread_mutex_lock ( &mutex );
/* Initialize the database (it just does nothing if it is already initialized) */
if ( !DB_out_init() )
_dpd.fatalMsg ( "AIPreproc: Unable to connect to output database '%s'\n", config->outdbname );
memset ( query, 0, sizeof ( query ));
snprintf ( query, sizeof ( query ),
"INSERT INTO %s ( alert1, alert2, correlation_coeff ) "
"VALUES ( %lu, %lu, %f )",
outdb_config[CORRELATED_ALERTS_TABLE],
corr->key.a->alert_id,
corr->key.b->alert_id,
corr->correlation );
DB_free_result ((DB_result) DB_out_query ( query ));
pthread_mutex_unlock ( &mutex );
pthread_exit ((void*) 0);
return 0;
} /* ----- end of function AI_store_correlation_to_db_thread ----- */
#endif

12
schemas/mysql.sql
View File

@ -50,7 +50,7 @@ CREATE TABLE ca_alerts (
timestamp datetime,
ip_hdr integer,
tcp_hdr integer,
cluster_id integer,
cluster_id integer default 0,
primary key(alert_id),
foreign key(ip_hdr) references ca_ip_headers(ip_hdr_id),
@ -71,12 +71,12 @@ CREATE TABLE ca_clustered_alerts (
DROP TABLE IF EXISTS ca_correlated_alerts;
CREATE TABLE ca_correlated_alerts (
cluster1 integer,
cluster2 integer,
alert1 integer,
alert2 integer,
correlation_coeff double,
primary key(cluster1, cluster2),
foreign key(cluster1) references ca_clustered_alerts(cluster_id),
foreign key(cluster2) references ca_clustered_alerts(cluster_id)
primary key(alert1, alert2),
foreign key(alert1) references ca_alerts(alert_id),
foreign key(alert2) references ca_alerts(alert_id)
);

1
spp_ai.c
View File

@ -747,6 +747,7 @@ static AI_config * AI_parse(char *args)
_dpd.fatalMsg ( "AIPreproc: Output database option used in config, but missing configuration option (all 'host', 'type', 'name', 'user', and 'password' options must be used)\n" );
}
AI_outdb_mutex_initialize();
_dpd.logMsg(" Saving output alerts to the database %s\n", config->outdbname );
}

31
spp_ai.h
View File

@ -359,6 +359,34 @@ typedef struct _AI_alert_event {
struct _AI_alert_event *next;
UT_hash_handle hh;
} AI_alert_event;
/*****************************************************************/
/** Simple structure for holding a couple of alerts to be merged, to be passed to the outdb thread */
typedef struct {
AI_snort_alert *alert1;
AI_snort_alert *alert2;
} AI_alerts_couple;
/*****************************************************************/
/** Key for the correlation hash table */
typedef struct {
/** First alert */
AI_snort_alert *a;
/** Second alert */
AI_snort_alert *b;
} AI_alert_correlation_key;
/*****************************************************************/
/** Struct representing the correlation between all the couples of alerts */
typedef struct {
/** Hash key */
AI_alert_correlation_key key;
/** Correlation coefficient */
double correlation;
/** Make the struct 'hashable' */
UT_hash_handle hh;
} AI_alert_correlation;
/*****************************************************************/
int preg_match ( const char*, char*, char***, int* );
char* str_replace ( char*, char*, char *);
@ -391,7 +419,10 @@ const AI_alert_event* AI_get_alert_events_by_key ( AI_alert_event_key );
unsigned int AI_get_history_alert_number ();
double AI_alert_bayesian_correlation ( AI_snort_alert *a, AI_snort_alert *b );
void AI_outdb_mutex_initialize ();
void* AI_store_alert_to_db_thread ( void* );
void* AI_store_cluster_to_db_thread ( void* );
void* AI_store_correlation_to_db_thread ( void* );
/** Function pointer to the function used for getting the alert list (from log file, db, ...) */
extern AI_snort_alert* (*get_alerts)(void);