Name:AWS Concurrent Sessions From Different Ips id:51c04fdb-2746-465a-b86e-b413a09c9085 version:4 date:2024-09-30 author:Bhavin Patel, Splunk status:production type:TTP Description:The following analytic identifies an AWS IAM account with concurrent sessions originating from more than one unique IP address within a 5-minute window. It leverages AWS CloudTrail logs, specifically the `DescribeEventAggregates` event, to detect this behavior. This activity is significant as it may indicate a session hijacking attack, where an adversary uses stolen session cookies to access AWS resources from a different location. If confirmed malicious, this could allow unauthorized access to sensitive corporate resources, leading to potential data breaches or further exploitation within the AWS environment. Data_source:
-AWS CloudTrail DescribeEventAggregates
search:`cloudtrail` eventName = DescribeEventAggregates src_ip!="AWS Internal" | bin span=5m _time | stats values(userAgent) values(eventName) values(src_ip) as src_ip dc(src_ip) as distinct_ip_count by _time user_arn | where distinct_ip_count > 1 | `aws_concurrent_sessions_from_different_ips_filter`
how_to_implement:You must install Splunk AWS Add on and Splunk App for AWS. This search works with AWS CloudTrail logs. known_false_positives:A user with concurrent sessions from different Ips may also represent the legitimate use of more than one device. Filter as needed and/or customize the threshold to fit your environment. References: -https://attack.mitre.org/techniques/T1185/ -https://breakdev.org/evilginx-2-next-generation-of-phishing-2fa-tokens/ -https://github.com/kgretzky/evilginx2 drilldown_searches: name:'View the detection results for - "$user_arn$"' search:'%original_detection_search% | search user_arn = "$user_arn$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for - "$user_arn$"' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user_arn$") starthoursago=168 | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' tags: analytic_story: - 'Compromised User Account' - 'AWS Identity and Access Management Account Takeover' asset_type:AWS Account confidence:60 impact:70 message:User $user_arn$ has concurrent sessions from more than one unique IP address $src_ip$ in the span of 5 minutes. mitre_attack_id: - 'T1185' observable: name:'user_arn' type:'User' - role: - 'Victim' name:'src_ip' type:'IP Address' - role: - 'Attacker' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' required_fields: - '_time' - 'eventName' - 'userAgent' - 'errorCode' - 'user_arn' - 'aws_account_id' - 'src_ip' risk_score:42 security_domain:threat
