Name:ESXi SSH Brute Force id:68fe4efa-bbbb-44ee-9f09-d07d2f0f346b version:5 date:None author:Raven Tait, Splunk status:production type:Anomaly Description:This detection identifies signs of SSH brute-force attacks by monitoring for a high number of failed login attempts within a short time frame. Such activity may indicate an attacker attempting to gain unauthorized access through password guessing. Data_source:
-VMWare ESXi Syslog
search:`esxi_syslog` Message="*Authentication failure for*" | rex "for (?<user>[\w]+) from (?<src_ip>\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})" | rex field=_raw "Z (?<dest>[\w\.]+)\s" | bin _time span=5m | stats min(_time) as firstTime max(_time) as lastTime count by user, src_ip, dest | where count > 10 | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `esxi_ssh_brute_force_filter`
how_to_implement:This is based on syslog data generated by VMware ESXi hosts. To implement this search, you must configure your ESXi systems to forward syslog output to your Splunk deployment. These logs must be ingested with the appropriate Splunk Technology Add-on for VMware ESXi Logs, which provides field extractions and CIM compatibility. known_false_positives:Limited false positives in most environments, however tune as needed. References: drilldown_searches: name:'View the detection results for - "$dest$"' search:'%original_detection_search% | search dest = "$dest$"' earliest_offset:'$info_min_time$' latest_offset:'$info_max_time$' name:'View risk events for the last 7 days for - "$dest$"' search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") | 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:'7d' latest_offset:'0' analytic_story:['Hellcat Ransomware', 'ESXi Post Compromise', 'Black Basta Ransomware']
