splApache-2.0from splunk/security_content

Detect Password Spray Attack Behavior On User

The following analytic identifies any user failing to authenticate from 10 or more unique sources. This behavior could represent an adversary performing a Password Spraying attack to obtain initial access or elevate privileges. This logic can be used for real time security monitoring as well as threat hunting exercises. Environments can be very different depending on the organization. Test and customize this detections thresholds as needed

Quality

FP risk

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Forks

Views

Rule sourcedetections/endpoint/detect_password_spray_attack_behavior_on_user.yml

| tstats `security_content_summariesonly` max(_time) as lastTime, min(_time) as firstTime, values(Authentication.user_category) as user_category values(Authentication.src_category) as src_category values(Authentication.app) as app count FROM datamodel=Authentication.Authentication
  BY Authentication.action Authentication.app Authentication.authentication_method
     Authentication.dest Authentication.signature Authentication.signature_id
     Authentication.src Authentication.user
| `drop_dm_object_name("Authentication")`
| eval user=case((match(upper(user),"[a-zA-Z0-9]{3}")),upper(user),true(),null), success=if(action="success",count,0), src=upper(src), success_src=if(action="success",src,null), failure=if(action="failure",count,0), failed_src=if(action="failure",src,null)
| stats count min(firstTime) as firstTime max(lastTime) as lastTime values(app) as app values(src_category) as src_category values(success_src) as src values(failed_src) as failed_src dc(success_src) as success_dc dc(failed_src) as failed_dc dc(src) as src_dc, sum(failure) as failure, sum(success) as success
  BY user
| fields - _time
| where src_dc >= 10 AND .25 > (success/failure) AND failed_dc > success_dc
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `detect_password_spray_attack_behavior_on_user_filter`