Microsoft Sentinel Analytic Rules
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Identify SysAid Server web shell creation

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Id50eb4cbd-188f-44f4-b964-bab84dcdec10
RulenameIdentify SysAid Server web shell creation
DescriptionThis query looks for potential webshell creation by the threat actor Mercury after the sucessful exploitation of SysAid server.

Reference: https://www.microsoft.com/security/blog/2022/08/25/mercury-leveraging-log4j-2-vulnerabilities-in-unpatched-systems-to-target-israeli-organizations/
SeverityHigh
TacticsInitialAccess
TechniquesT1190
Required data connectorsMicrosoftThreatProtection
SecurityEvents
KindScheduled
Query frequency1d
Query period1d
Trigger threshold0
Trigger operatorgt
Source Urihttps://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Web Shells Threat Protection/Analytic Rules/PotentialMercury_Webshell.yaml
Version1.0.2
Arm template50eb4cbd-188f-44f4-b964-bab84dcdec10.json
Deploy To Azure
let timeframe = 1d;
let time_window = 5m;
(union isfuzzy=true
(SecurityEvent
| where TimeGenerated > ago(timeframe)
| where EventID == 4688
| where Process has_any ("java.exe", "javaw.exe") and CommandLine has "SysAidServer" 
| summarize by ParentProcessName,Process, Account, Computer, CommandLine, timekey= bin(TimeGenerated, time_window), TimeGenerated, SubjectLogonId
| join kind=inner(
SecurityEvent
| where TimeGenerated > ago(timeframe)
| where EventID == 4663
| where Process has_any ("java.exe", "javaw.exe")
| where AccessMask in ('0x2','0x100', '0x10', '0x4')
| where ObjectName endswith ".jsp" 
| summarize by ParentProcessName, Account, Computer, ObjectName, ProcessName, timekey= bin(TimeGenerated, time_window), TimeGenerated, SubjectLogonId)
 on timekey, Computer, SubjectLogonId
),
(DeviceFileEvents 
| where InitiatingProcessFileName has_any ("java.exe", "javaw.exe")  
| where InitiatingProcessCommandLine has "SysAidServer"  
| where FileName endswith ".jsp" 
| extend Account = strcat(InitiatingProcessAccountDomain, @'\', InitiatingProcessAccountName), Computer = DeviceName
),
(imFileEvent
| where TimeGenerated > ago(timeframe)
| where EventType == "FileCreated"
| where ActingProcessName has_any ("java.exe", "javaw.exe") 
| where ActingProcessCommandLine has "SysAidServer"  
| where FilePath endswith ".jsp" 
| extend Account = ActorUsername, Computer = DvcHostname
)
)
| extend AccountName = tostring(split(Account, @'\')[1]), AccountNTDomain = tostring(split(Account, @'\')[0])
| extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
tags:
- Mercury
- SchemaVersion: 0.1.0
  Schema: ASIMFileEvent
description: |
  'This query looks for potential webshell creation by the threat actor Mercury after the sucessful exploitation of SysAid server. 
  Reference:  https://www.microsoft.com/security/blog/2022/08/25/mercury-leveraging-log4j-2-vulnerabilities-in-unpatched-systems-to-target-israeli-organizations/'  
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Web Shells Threat Protection/Analytic Rules/PotentialMercury_Webshell.yaml
version: 1.0.2
triggerThreshold: 0
kind: Scheduled
queryPeriod: 1d
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: Account
    identifier: FullName
  - columnName: AccountName
    identifier: Name
  - columnName: AccountNTDomain
    identifier: NTDomain
- entityType: Host
  fieldMappings:
  - columnName: Computer
    identifier: FullName
  - columnName: HostName
    identifier: HostName
  - columnName: HostNameDomain
    identifier: DnsDomain
requiredDataConnectors:
- connectorId: SecurityEvents
  dataTypes:
  - SecurityEvent
- connectorId: MicrosoftThreatProtection
  dataTypes:
  - DeviceFileEvents
triggerOperator: gt
id: 50eb4cbd-188f-44f4-b964-bab84dcdec10
name: Identify SysAid Server web shell creation
query: |
  let timeframe = 1d;
  let time_window = 5m;
  (union isfuzzy=true
  (SecurityEvent
  | where TimeGenerated > ago(timeframe)
  | where EventID == 4688
  | where Process has_any ("java.exe", "javaw.exe") and CommandLine has "SysAidServer" 
  | summarize by ParentProcessName,Process, Account, Computer, CommandLine, timekey= bin(TimeGenerated, time_window), TimeGenerated, SubjectLogonId
  | join kind=inner(
  SecurityEvent
  | where TimeGenerated > ago(timeframe)
  | where EventID == 4663
  | where Process has_any ("java.exe", "javaw.exe")
  | where AccessMask in ('0x2','0x100', '0x10', '0x4')
  | where ObjectName endswith ".jsp" 
  | summarize by ParentProcessName, Account, Computer, ObjectName, ProcessName, timekey= bin(TimeGenerated, time_window), TimeGenerated, SubjectLogonId)
   on timekey, Computer, SubjectLogonId
  ),
  (DeviceFileEvents 
  | where InitiatingProcessFileName has_any ("java.exe", "javaw.exe")  
  | where InitiatingProcessCommandLine has "SysAidServer"  
  | where FileName endswith ".jsp" 
  | extend Account = strcat(InitiatingProcessAccountDomain, @'\', InitiatingProcessAccountName), Computer = DeviceName
  ),
  (imFileEvent
  | where TimeGenerated > ago(timeframe)
  | where EventType == "FileCreated"
  | where ActingProcessName has_any ("java.exe", "javaw.exe") 
  | where ActingProcessCommandLine has "SysAidServer"  
  | where FilePath endswith ".jsp" 
  | extend Account = ActorUsername, Computer = DvcHostname
  )
  )
  | extend AccountName = tostring(split(Account, @'\')[1]), AccountNTDomain = tostring(split(Account, @'\')[0])
  | extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
  | extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)  
tactics:
- InitialAccess
queryFrequency: 1d
relevantTechniques:
- T1190
metadata:
  support:
    tier: Community
  categories:
    domains:
    - Security - Others
  author:
    name: Microsoft Security Research
  source:
    kind: Scheduled
severity: High
{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2023-02-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/50eb4cbd-188f-44f4-b964-bab84dcdec10')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/50eb4cbd-188f-44f4-b964-bab84dcdec10')]",
      "properties": {
        "alertRuleTemplateName": "50eb4cbd-188f-44f4-b964-bab84dcdec10",
        "customDetails": null,
        "description": "'This query looks for potential webshell creation by the threat actor Mercury after the sucessful exploitation of SysAid server. \nReference:  https://www.microsoft.com/security/blog/2022/08/25/mercury-leveraging-log4j-2-vulnerabilities-in-unpatched-systems-to-target-israeli-organizations/'\n",
        "displayName": "Identify SysAid Server web shell creation",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "Account",
                "identifier": "FullName"
              },
              {
                "columnName": "AccountName",
                "identifier": "Name"
              },
              {
                "columnName": "AccountNTDomain",
                "identifier": "NTDomain"
              }
            ]
          },
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "Computer",
                "identifier": "FullName"
              },
              {
                "columnName": "HostName",
                "identifier": "HostName"
              },
              {
                "columnName": "HostNameDomain",
                "identifier": "DnsDomain"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Web Shells Threat Protection/Analytic Rules/PotentialMercury_Webshell.yaml",
        "query": "let timeframe = 1d;\nlet time_window = 5m;\n(union isfuzzy=true\n(SecurityEvent\n| where TimeGenerated > ago(timeframe)\n| where EventID == 4688\n| where Process has_any (\"java.exe\", \"javaw.exe\") and CommandLine has \"SysAidServer\" \n| summarize by ParentProcessName,Process, Account, Computer, CommandLine, timekey= bin(TimeGenerated, time_window), TimeGenerated, SubjectLogonId\n| join kind=inner(\nSecurityEvent\n| where TimeGenerated > ago(timeframe)\n| where EventID == 4663\n| where Process has_any (\"java.exe\", \"javaw.exe\")\n| where AccessMask in ('0x2','0x100', '0x10', '0x4')\n| where ObjectName endswith \".jsp\" \n| summarize by ParentProcessName, Account, Computer, ObjectName, ProcessName, timekey= bin(TimeGenerated, time_window), TimeGenerated, SubjectLogonId)\n on timekey, Computer, SubjectLogonId\n),\n(DeviceFileEvents \n| where InitiatingProcessFileName has_any (\"java.exe\", \"javaw.exe\")  \n| where InitiatingProcessCommandLine has \"SysAidServer\"  \n| where FileName endswith \".jsp\" \n| extend Account = strcat(InitiatingProcessAccountDomain, @'\\', InitiatingProcessAccountName), Computer = DeviceName\n),\n(imFileEvent\n| where TimeGenerated > ago(timeframe)\n| where EventType == \"FileCreated\"\n| where ActingProcessName has_any (\"java.exe\", \"javaw.exe\") \n| where ActingProcessCommandLine has \"SysAidServer\"  \n| where FilePath endswith \".jsp\" \n| extend Account = ActorUsername, Computer = DvcHostname\n)\n)\n| extend AccountName = tostring(split(Account, @'\\')[1]), AccountNTDomain = tostring(split(Account, @'\\')[0])\n| extend HostName = tostring(split(Computer, \".\")[0]), DomainIndex = toint(indexof(Computer, '.'))\n| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P1D",
        "severity": "High",
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "InitialAccess"
        ],
        "tags": [
          "Mercury",
          {
            "Schema": "ASIMFileEvent",
            "SchemaVersion": "0.1.0"
          }
        ],
        "techniques": [
          "T1190"
        ],
        "templateVersion": "1.0.2",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}