VMware ESXi - Multiple Failed Shell Login via SSH

// To Adapt to your environment
let triggerThreshold = 10;
VMwareESXi
| where SyslogMessage has "sshd"
| where SyslogMessage contains "authentication failure"
| extend SrcUsername = extract(@'\[info\]\s+\[(.*?)\]', 1, SyslogMessage)
| extend DstHostname = extract(@'\[\d+\]\s+\[(.*?)\s+on', 1, SyslogMessage)
| extend SrcIpAddr = extract(@'\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})', 1, SyslogMessage)
| summarize make_set(SrcUsername),count() by SrcIpAddr,DstHostname
| where count_ >= triggerThreshold
| extend HostCustomEntity = DstHostname

requiredDataConnectors:
- datatypes:
  - Syslog
  connectorId: SyslogAma
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/VMWareESXi/Analytic%20Rules/ESXiMultipleFailedSSHLogin.yaml
version: 1.0.0
status: Available
queryFrequency: 10m
query: |
  // To Adapt to your environment
  let triggerThreshold = 10;
  VMwareESXi
  | where SyslogMessage has "sshd"
  | where SyslogMessage contains "authentication failure"
  | extend SrcUsername = extract(@'\[info\]\s+\[(.*?)\]', 1, SyslogMessage)
  | extend DstHostname = extract(@'\[\d+\]\s+\[(.*?)\s+on', 1, SyslogMessage)
  | extend SrcIpAddr = extract(@'\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})', 1, SyslogMessage)
  | summarize make_set(SrcUsername),count() by SrcIpAddr,DstHostname
  | where count_ >= triggerThreshold
  | extend HostCustomEntity = DstHostname
tactics:
- CredentialAccess
relevantTechniques:
- T1110
id: 22d177d5-588c-4f1a-a332-2695f52079bb
triggerThreshold: 0
triggerOperator: gt
name: VMware ESXi - Multiple Failed Shell Login via SSH
queryPeriod: 10m
severity: Medium
entityMappings:
- fieldMappings:
  - columnName: HostCustomEntity
    identifier: FullName
  entityType: Host
- fieldMappings:
  - columnName: SrcIpAddr
    identifier: Address
  entityType: IP
kind: Scheduled
description: |
  Identifies a failed ESXi Shell login via SSH in a short TimeFrame. This could be suspicious activity especially if this alert is seen triggering many times within a short time frame which could be evidence of a brute-force attack. TriggerThreshold can be adapted. 

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2024-01-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/22d177d5-588c-4f1a-a332-2695f52079bb')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/22d177d5-588c-4f1a-a332-2695f52079bb')]",
      "properties": {
        "alertRuleTemplateName": "22d177d5-588c-4f1a-a332-2695f52079bb",
        "customDetails": null,
        "description": "Identifies a failed ESXi Shell login via SSH in a short TimeFrame. This could be suspicious activity especially if this alert is seen triggering many times within a short time frame which could be evidence of a brute-force attack. TriggerThreshold can be adapted. \n",
        "displayName": "VMware ESXi - Multiple Failed Shell Login via SSH",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "HostCustomEntity",
                "identifier": "FullName"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "SrcIpAddr",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/VMWareESXi/Analytic%20Rules/ESXiMultipleFailedSSHLogin.yaml",
        "query": "// To Adapt to your environment\nlet triggerThreshold = 10;\nVMwareESXi\n| where SyslogMessage has \"sshd\"\n| where SyslogMessage contains \"authentication failure\"\n| extend SrcUsername = extract(@'\\[info\\]\\s+\\[(.*?)\\]', 1, SyslogMessage)\n| extend DstHostname = extract(@'\\[\\d+\\]\\s+\\[(.*?)\\s+on', 1, SyslogMessage)\n| extend SrcIpAddr = extract(@'\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3})', 1, SyslogMessage)\n| summarize make_set(SrcUsername),count() by SrcIpAddr,DstHostname\n| where count_ >= triggerThreshold\n| extend HostCustomEntity = DstHostname\n",
        "queryFrequency": "PT10M",
        "queryPeriod": "PT10M",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "CredentialAccess"
        ],
        "techniques": [
          "T1110"
        ],
        "templateVersion": "1.0.0",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}