AlienVault Correlation
            Alexander Goller
           Solution Architect
Why do we need correlation?
Or how to make sense out of all that information.
What do we see in our daily business?
Too much data, not enough information
Noise
Events with no (obvious) meaning
Correlation to the rescue
What correlation does for us

  Increase evidence
      Does the event have business impact?
      Is the event dangerous?
      Is the event a false positive?
Correlation to the rescue
What correlation does for us

  Security automation
      Relate data together to produce
      information
      Get rid of manual monitoring of logs
      Find well-known threats in the millions of
      events you are receiving
How correlation works
An insight to the AlienVault correlation engine
Correlation explained
  A simple use case




                                        Correlation rule will
                 Matches correlation
                                         raise priority and
                     criteria (e.g.
                                          reliability of the    Increased risk will
Incoming event   Destination belongs
                                       event as specified in      create an alert
                  to our VIP server
                                          the correlation
                         zone)
                                              directive
Features

 Correlation rules can nest any level
 AND condition: branch another level
 OR condition: insert a new rule on
 same level
Examples

 Somebody does a config change to an
 internal asset
 Give more meaning to authentications to
 a very important host or zone of your
 network
 Give an event a more meaningful
 signature
 Map event to PCI/ISO objectives to get
 rapid reports on compliance
Correlation explained
Sample complex use cases

     Incoming events                                           Alert reinserted
                                                               into event queue


        One failed ssh login to VIP host


            3 failed logins in the next 60 seconds


                 3 more failed logins in the next 5 minutes


                     Correlation rule will generate an alert
Threat detetion examples

  Correlate firewall events to detect common
  DoS and DDoS attacks
  Prebuilt AlienVault correlation directives
  cover a lot of those already
  Modify for your environment
  Build Security Intelligence
Correlation explained
Complex use case with mixed events

                                                            Alert reinserted
      Incoming events                                       into event queue




         Succesful SSH login to VIP host



             Service going down on host



                  Correlation rule will generate an alert
Threat detetion examples

  Correlate firewall events to detect common
  DoS and DDoS attacks
  Prebuilt AlienVault correlation directives
  cover a lot of those already
  Modify for your environment
  Build Security Intelligence
Correlation directives
Top level

  Directive name
    e.g. „Login to DMZ host from outside“
  Priority
    Value of 0-5 stating the initial importance of
    the event
  Rule ID
    Correlation editor automatically creates one
    CLI editing requires you to choose a unique
    ID
Editor only: Start adding a directive

  Top level directive
  Name
  Priority
First level

  Every event received can activate directives
     Firewall permits
     Logins
     Oracle audit events
     No limits
  Limitations
     Only one event will activate a directive
     Only events from detector plugins allowed
     No timeout required
Editor only: Create first level rule

  Create rule, explain dialogs
  Save directive
  Restart server
Deeper correlation levels
  Any number of events within a specified
  timeout
  Match on any attribute from previous rules
    Event must have same source IP
    Event must have same destination IP
    Event must have same event type as on previous
    levels
Editor only:

  Create deeper rules for sample
  complex use case.
What‘s next?
How to deal with alerts from the correlation engine
What‘s next

  Generated event has a risk > 1
    automatically becomes alert
  Use Policies & Actions
    Email notification
    Custom user script
    Open a internal ticket
  Map to compliance objectives
    PCI: e.g. Access to a PCI host from the internet
    ISO: monitor firewall changes
Want more?
Attend OSSIM Made Simple
Open Source. Open Tools. Open Minds.

Creating Correlation Rules in AlienVault

  • 1.
    AlienVault Correlation Alexander Goller Solution Architect
  • 2.
    Why do weneed correlation? Or how to make sense out of all that information.
  • 3.
    What do wesee in our daily business? Too much data, not enough information
  • 4.
    Noise Events with no(obvious) meaning
  • 5.
    Correlation to therescue What correlation does for us Increase evidence Does the event have business impact? Is the event dangerous? Is the event a false positive?
  • 6.
    Correlation to therescue What correlation does for us Security automation Relate data together to produce information Get rid of manual monitoring of logs Find well-known threats in the millions of events you are receiving
  • 7.
    How correlation works Aninsight to the AlienVault correlation engine
  • 8.
    Correlation explained A simple use case Correlation rule will Matches correlation raise priority and criteria (e.g. reliability of the Increased risk will Incoming event Destination belongs event as specified in create an alert to our VIP server the correlation zone) directive
  • 9.
    Features Correlation rulescan nest any level AND condition: branch another level OR condition: insert a new rule on same level
  • 10.
    Examples Somebody doesa config change to an internal asset Give more meaning to authentications to a very important host or zone of your network Give an event a more meaningful signature Map event to PCI/ISO objectives to get rapid reports on compliance
  • 11.
    Correlation explained Sample complexuse cases Incoming events Alert reinserted into event queue One failed ssh login to VIP host 3 failed logins in the next 60 seconds 3 more failed logins in the next 5 minutes Correlation rule will generate an alert
  • 12.
    Threat detetion examples Correlate firewall events to detect common DoS and DDoS attacks Prebuilt AlienVault correlation directives cover a lot of those already Modify for your environment Build Security Intelligence
  • 13.
    Correlation explained Complex usecase with mixed events Alert reinserted Incoming events into event queue Succesful SSH login to VIP host Service going down on host Correlation rule will generate an alert
  • 14.
    Threat detetion examples Correlate firewall events to detect common DoS and DDoS attacks Prebuilt AlienVault correlation directives cover a lot of those already Modify for your environment Build Security Intelligence
  • 15.
  • 16.
    Top level Directive name e.g. „Login to DMZ host from outside“ Priority Value of 0-5 stating the initial importance of the event Rule ID Correlation editor automatically creates one CLI editing requires you to choose a unique ID
  • 17.
    Editor only: Startadding a directive Top level directive Name Priority
  • 18.
    First level Every event received can activate directives Firewall permits Logins Oracle audit events No limits Limitations Only one event will activate a directive Only events from detector plugins allowed No timeout required
  • 19.
    Editor only: Createfirst level rule Create rule, explain dialogs Save directive Restart server
  • 20.
    Deeper correlation levels Any number of events within a specified timeout Match on any attribute from previous rules Event must have same source IP Event must have same destination IP Event must have same event type as on previous levels
  • 21.
    Editor only: Create deeper rules for sample complex use case.
  • 22.
    What‘s next? How todeal with alerts from the correlation engine
  • 23.
    What‘s next Generated event has a risk > 1 automatically becomes alert Use Policies & Actions Email notification Custom user script Open a internal ticket Map to compliance objectives PCI: e.g. Access to a PCI host from the internet ISO: monitor firewall changes
  • 24.
  • 25.
    Open Source. OpenTools. Open Minds.

Editor's Notes

  • #20 Create rule, explain dialogsSave directiveRestart server