diff --git a/detections/cloud/o365_bypass_mfa_via_trusted_ip.yml b/detections/cloud/o365_bypass_mfa_via_trusted_ip.yml index 8cea3ed666..f7f7620d2e 100644 --- a/detections/cloud/o365_bypass_mfa_via_trusted_ip.yml +++ b/detections/cloud/o365_bypass_mfa_via_trusted_ip.yml @@ -1,21 +1,26 @@ author: Bhavin Patel, Splunk date: '2021-01-12' -description: This search detects newly added IP addresses/CIDR blocks to the list of MFA Trusted IPs to bypass multi factor authentication. Attackers are often known to use this technique so that they can bypass the MFA system. +description: This search detects newly added IP addresses/CIDR blocks to the list + of MFA Trusted IPs to bypass multi factor authentication. Attackers are often known + to use this technique so that they can bypass the MFA system. how_to_implement: You must install Splunk Microsoft Office 365 add-on. This search works with o365:management:activity id: c783dd98-c703-4252-9e8a-f19d9f66949e -known_false_positives: Unless it is a special case, it is uncommon to continually update Trusted IPs to MFA configuration. +known_false_positives: Unless it is a special case, it is uncommon to continually + update Trusted IPs to MFA configuration. name: O365 Bypass MFA via Trusted IP references: - https://i.blackhat.com/USA-20/Thursday/us-20-Bienstock-My-Cloud-Is-APTs-Cloud-Investigating-And-Defending-Office-365.pdf - https://attack.mitre.org/techniques/T1562/007/ search: '`o365_management_activity` signature="Set Company Information." ModifiedProperties{}.Name=StrongAuthenticationPolicy -| rex max_match=100 field=ModifiedProperties{}.NewValue "(?\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\/\d{1,2})" -| rex max_match=100 field=ModifiedProperties{}.OldValue "(?\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\/\d{1,2})" -| eval ip_addresses_old=if(isnotnull(ip_addresses_old),ip_addresses_old,"0") -| mvexpand ip_addresses_new_added -| where isnull(mvfind(ip_addresses_old,ip_addresses_new_added)) -|stats count min(_time) as firstTime max(_time) as lastTime values(ip_addresses_old) as ip_addresses_old by user ip_addresses_new_added signature vendor_product vendor_account status user_id action | `security_content_ctime(firstTime)`| `security_content_ctime(lastTime)`| `o365_bypass_mfa_via_trusted_ip_filter`' + | rex max_match=100 field=ModifiedProperties{}.NewValue "(?\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\/\d{1,2})" + | rex max_match=100 field=ModifiedProperties{}.OldValue "(?\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\/\d{1,2})" + | eval ip_addresses_old=if(isnotnull(ip_addresses_old),ip_addresses_old,"0") | mvexpand + ip_addresses_new_added | where isnull(mvfind(ip_addresses_old,ip_addresses_new_added)) + |stats count min(_time) as firstTime max(_time) as lastTime values(ip_addresses_old) + as ip_addresses_old by user ip_addresses_new_added signature vendor_product vendor_account + status user_id action | `security_content_ctime(firstTime)`| `security_content_ctime(lastTime)`| + `o365_bypass_mfa_via_trusted_ip_filter`' tags: analytics_story: - Office 365 Detections @@ -25,5 +30,8 @@ tags: mitre_attack_id: - T1562.007 security_domain: threat + automated_detection_testing: passed + dataset: + - https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1562.007/o365_bypass_mfa_via_trusted_ip/o365_bypass_mfa_via_trusted_ip.json type: ESCU version: 1