Name:ESXi Reverse Shell Patterns id:ee8b16a4-118e-4dd7-af4b-835530415610 version:1 date:2025-05-12 author:Raven Tait, Splunk status:production type:TTP Description:This detection looks for reverse shell string patterns on an ESXi host, which may indicate that a threat actor is attempting to establish remote control over the system. Data_source:
-VMWare ESXi Syslog
search:`esxi_syslog` Message IN ("*bash -i >&*","*/dev/tcp/*","*/dev/udp/*", "*/socat exec:*","*socket(S,PF_INET*") OR (Message="*python -c*" AND Message="*import socket*") | rex field=_raw "Z (?<dest>[\w\.]+)\s" | stats min(_time) as firstTime max(_time) as lastTime count by dest Message | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `esxi_reverse_shell_patterns_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 ("$dest$") 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: - 'ESXi Post Compromise' - 'Black Basta Ransomware' asset_type:Infrastructure mitre_attack_id: - 'T1059' product: - 'Splunk Enterprise' - 'Splunk Enterprise Security' - 'Splunk Cloud' security_domain:endpoint
