Identify SysAid Server web shell creation

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Id	50eb4cbd-188f-44f4-b964-bab84dcdec10
Rulename	Identify SysAid Server web shell creation
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/
Severity	High
Tactics	InitialAccess
Techniques	T1190
Required data connectors	MicrosoftThreatProtection SecurityEvents WindowsSecurityEvents
Kind	Scheduled
Query frequency	1d
Query period	1d
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Web Shells Threat Protection/Analytic Rules/PotentialMercury_Webshell.yaml
Version	1.0.3
Arm template	50eb4cbd-188f-44f4-b964-bab84dcdec10.json

KQL

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)

YAML

version: 1.0.3
triggerOperator: gt
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Web Shells Threat Protection/Analytic Rules/PotentialMercury_Webshell.yaml
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/'  
queryFrequency: 1d
name: Identify SysAid Server web shell creation
tactics:
- InitialAccess
triggerThreshold: 0
id: 50eb4cbd-188f-44f4-b964-bab84dcdec10
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)  
severity: High
metadata:
  categories:
    domains:
    - Security - Others
  source:
    kind: Scheduled
  support:
    tier: Community
  author:
    name: Microsoft Security Research
tags:
- Mercury
- SchemaVersion: 0.1.0
  Schema: ASIMFileEvent
queryPeriod: 1d
entityMappings:
- fieldMappings:
  - columnName: Account
    identifier: FullName
  - columnName: AccountName
    identifier: Name
  - columnName: AccountNTDomain
    identifier: NTDomain
  entityType: Account
- fieldMappings:
  - columnName: Computer
    identifier: FullName
  - columnName: HostName
    identifier: HostName
  - columnName: HostNameDomain
    identifier: DnsDomain
  entityType: Host
relevantTechniques:
- T1190
kind: Scheduled
requiredDataConnectors:
- connectorId: SecurityEvents
  dataTypes:
  - SecurityEvent
- connectorId: WindowsSecurityEvents
  dataTypes:
  - SecurityEvent
- connectorId: MicrosoftThreatProtection
  dataTypes:
  - DeviceFileEvents

ARM