Detection rules › Splunk
ESXi VM Exported via Remote Tool
This detection identifies the use of a remote tool to download virtual machine disk files from a datastore. The NFC protocol is used by management tools to transfer files to and from ESXi hosts, but it can also be abused by attackers or insiders to exfiltrate full virtual disk images
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Collection | T1005 Data from Local System |
Rule body splunk
name: ESXi VM Exported via Remote Tool
id: 2e155547-aaac-49d3-b0ef-ceabc31fd364
version: 4
creation_date: '2025-07-11'
modification_date: '2026-05-13'
author: Raven Tait, Splunk
status: production
type: TTP
description: This detection identifies the use of a remote tool to download virtual machine disk files from a datastore. The NFC protocol is used by management tools to transfer files to and from ESXi hosts, but it can also be abused by attackers or insiders to exfiltrate full virtual disk images
data_source:
- VMWare ESXi Syslog
search: '`esxi_syslog` Message="*File download from path*" Message="*was initiated from*" | rex field=_raw "from path ''\[(?<Datastore>[^\]]+)\](?<VMPath>[^'']+)''" | rex field=_raw "initiated from ''(?<InitiatorTool>[^/]+)/(?<ToolVersion>[^@]+)@(?<InitiatorIP>\d{1,3}(?:\.\d{1,3}){3})''" | rex field=_raw "Z (?<dest>[\w\.]+)\s" | stats min(_time) as firstTime max(_time) as lastTime count by Datastore VMPath InitiatorTool ToolVersion InitiatorIP dest | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `esxi_vm_exported_via_remote_tool_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: Administrators may use this command when troubleshooting. Tune as needed.
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"
finding:
title: VM downloaded from datastore on ESXi host $dest$.
entity:
field: dest
type: system
score: 50
analytic_story:
- ESXi Post Compromise
- Black Basta Ransomware
asset_type: Infrastructure
mitre_attack_id:
- T1005
product:
- Splunk Enterprise
- Splunk Enterprise Security
- Splunk Cloud
category: application
security_domain: endpoint
tests:
- name: True Positive Test
attack_data:
- data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1005/esxi_vm_download/esxi_vm_download.log
source: vmware:esxlog
sourcetype: vmw-syslog
test_type: unit
Stages and Predicates
Stage 1: search
`esxi_syslog` Message="*File download from path*" Message="*was initiated from*"
Stage 2: rex
| rex field=_raw "from path '\[(?<Datastore>[^\]]+)\](?<VMPath>[^']+)'"
Stage 3: rex
| rex field=_raw "initiated from '(?<InitiatorTool>[^/]+)/(?<ToolVersion>[^@]+)@(?<InitiatorIP>\d{1,3}(?:\.\d{1,3}){3})'"
Stage 4: rex
| rex field=_raw "Z (?<dest>[\w\.]+)\s"
Stage 5: stats
| stats min(_time) as firstTime max(_time) as lastTime count by Datastore VMPath InitiatorTool ToolVersion InitiatorIP dest
Stage 6: search
| `security_content_ctime(firstTime)`
Stage 7: search
| `security_content_ctime(lastTime)`
Stage 8: search
| `esxi_vm_exported_via_remote_tool_filter`
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
Message | eq |
|
sourcetype | in |
|