High count of failed attempts from same client IP

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Id	19e01883-15d8-4eb6-a7a5-3276cd668388
Rulename	High count of failed attempts from same client IP
Description	Identifies when 20 or more failed attempts from a given client IP in 1 minute occur on the IIS server. This could be indicative of an attempted brute force. This could also simply indicate a misconfigured service or device. Recommendations: Validate that these are expected connections from the given Client IP. If the client IP is not recognized, potentially block these connections at the edge device. If these are expected connections, verify the credentials are properly configured on the system, service, application or device that is associated with the client IP. References: IIS status code mapping: https://support.microsoft.com/help/943891/the-http-status-code-in-iis-7-0-iis-7-5-and-iis-8-0 Win32 Status code mapping: https://msdn.microsoft.com/library/cc231199.aspx
Severity	Medium
Tactics	CredentialAccess
Techniques	T1110
Required data connectors	AzureMonitor(IIS)
Kind	Scheduled
Query frequency	1d
Query period	1d
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Detections/W3CIISLog/HighFailedLogonCountByClientIP.yaml
Version	1.0.4
Arm template	19e01883-15d8-4eb6-a7a5-3276cd668388.json

KQL

let timeBin = 1m;
let failedThreshold = 20;
W3CIISLog
| where scStatus in ("401","403")
| where csUserName != "-"
| extend scStatusFull = strcat(scStatus, ".",scSubStatus)
// Map common IIS codes
| extend scStatusFull_Friendly = case(
scStatusFull == "401.0", "Access denied.",
scStatusFull == "401.1", "Logon failed.",
scStatusFull == "401.2", "Logon failed due to server configuration.",
scStatusFull == "401.3", "Unauthorized due to ACL on resource.",
scStatusFull == "401.4", "Authorization failed by filter.",
scStatusFull == "401.5", "Authorization failed by ISAPI/CGI application.",
scStatusFull == "403.0", "Forbidden.",
scStatusFull == "403.4", "SSL required.",
"See - https://support.microsoft.com/help/943891/the-http-status-code-in-iis-7-0-iis-7-5-and-iis-8-0")
// Mapping to Hex so can be mapped using website in comments above
| extend scWin32Status_Hex = tohex(tolong(scWin32Status))
// Map common win32 codes
| extend scWin32Status_Friendly = case(
scWin32Status_Hex =~ "775", "The referenced account is currently locked out and cannot be logged on to.",
scWin32Status_Hex =~ "52e", "Logon failure: Unknown user name or bad password.",
scWin32Status_Hex =~ "532", "Logon failure: The specified account password has expired.",
scWin32Status_Hex =~ "533", "Logon failure: Account currently disabled.",
scWin32Status_Hex =~ "2ee2", "The request has timed out.",
scWin32Status_Hex =~ "0", "The operation completed successfully.",
scWin32Status_Hex =~ "1", "Incorrect function.",
scWin32Status_Hex =~ "2", "The system cannot find the file specified.",
scWin32Status_Hex =~ "3", "The system cannot find the path specified.",
scWin32Status_Hex =~ "4", "The system cannot open the file.",
scWin32Status_Hex =~ "5", "Access is denied.",
scWin32Status_Hex =~ "8009030e", "SEC_E_NO_CREDENTIALS",
scWin32Status_Hex =~ "8009030C", "SEC_E_LOGON_DENIED",
"See - https://msdn.microsoft.com/library/cc231199.aspx")
// decode URI when available
| extend decodedUriQuery = url_decode(csUriQuery)
// Count of failed attempts from same client IP
| summarize makeset(decodedUriQuery), makeset(csUserName), makeset(sSiteName), makeset(sPort), makeset(csUserAgent), makeset(csMethod), makeset(csUriQuery), makeset(scStatusFull), makeset(scStatusFull_Friendly), makeset(scWin32Status_Hex), makeset(scWin32Status_Friendly), FailedConnectionsCount = count() by bin(TimeGenerated, timeBin), cIP, Computer, sIP
| where FailedConnectionsCount >= failedThreshold
| project TimeGenerated, cIP, set_csUserName, set_decodedUriQuery, Computer, set_sSiteName, sIP, set_sPort, set_csUserAgent, set_csMethod, set_scStatusFull, set_scStatusFull_Friendly, set_scWin32Status_Hex, set_scWin32Status_Friendly, FailedConnectionsCount
| order by FailedConnectionsCount
| extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)

YAML

relevantTechniques:
- T1110
name: High count of failed attempts from same client IP
requiredDataConnectors:
- dataTypes:
  - W3CIISLog
  connectorId: AzureMonitor(IIS)
entityMappings:
- fieldMappings:
  - identifier: FullName
    columnName: Computer
  - identifier: HostName
    columnName: HostName
  - identifier: NTDomain
    columnName: HostNameDomain
  entityType: Host
- fieldMappings:
  - identifier: Address
    columnName: cIP
  entityType: IP
triggerThreshold: 0
id: 19e01883-15d8-4eb6-a7a5-3276cd668388
tactics:
- CredentialAccess
version: 1.0.4
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Detections/W3CIISLog/HighFailedLogonCountByClientIP.yaml
queryPeriod: 1d
kind: Scheduled
metadata:
  categories:
    domains:
    - Security - Network
    - Identity
  author:
    name: Microsoft Security Research
  support:
    tier: Community
  source:
    kind: Community
queryFrequency: 1d
severity: Medium
description: |
  'Identifies when 20 or more failed attempts from a given client IP in 1 minute occur on the IIS server.
  This could be indicative of an attempted brute force. This could also simply indicate a misconfigured service or device.
  Recommendations: Validate that these are expected connections from the given Client IP.  If the client IP is not recognized, potentially block these connections at the edge device.
  If these are expected connections, verify the credentials are properly configured on the system, service, application or device that is associated with the client IP.
  References:
  IIS status code mapping: https://support.microsoft.com/help/943891/the-http-status-code-in-iis-7-0-iis-7-5-and-iis-8-0
  Win32 Status code mapping: https://msdn.microsoft.com/library/cc231199.aspx'  
query: |
  let timeBin = 1m;
  let failedThreshold = 20;
  W3CIISLog
  | where scStatus in ("401","403")
  | where csUserName != "-"
  | extend scStatusFull = strcat(scStatus, ".",scSubStatus)
  // Map common IIS codes
  | extend scStatusFull_Friendly = case(
  scStatusFull == "401.0", "Access denied.",
  scStatusFull == "401.1", "Logon failed.",
  scStatusFull == "401.2", "Logon failed due to server configuration.",
  scStatusFull == "401.3", "Unauthorized due to ACL on resource.",
  scStatusFull == "401.4", "Authorization failed by filter.",
  scStatusFull == "401.5", "Authorization failed by ISAPI/CGI application.",
  scStatusFull == "403.0", "Forbidden.",
  scStatusFull == "403.4", "SSL required.",
  "See - https://support.microsoft.com/help/943891/the-http-status-code-in-iis-7-0-iis-7-5-and-iis-8-0")
  // Mapping to Hex so can be mapped using website in comments above
  | extend scWin32Status_Hex = tohex(tolong(scWin32Status))
  // Map common win32 codes
  | extend scWin32Status_Friendly = case(
  scWin32Status_Hex =~ "775", "The referenced account is currently locked out and cannot be logged on to.",
  scWin32Status_Hex =~ "52e", "Logon failure: Unknown user name or bad password.",
  scWin32Status_Hex =~ "532", "Logon failure: The specified account password has expired.",
  scWin32Status_Hex =~ "533", "Logon failure: Account currently disabled.",
  scWin32Status_Hex =~ "2ee2", "The request has timed out.",
  scWin32Status_Hex =~ "0", "The operation completed successfully.",
  scWin32Status_Hex =~ "1", "Incorrect function.",
  scWin32Status_Hex =~ "2", "The system cannot find the file specified.",
  scWin32Status_Hex =~ "3", "The system cannot find the path specified.",
  scWin32Status_Hex =~ "4", "The system cannot open the file.",
  scWin32Status_Hex =~ "5", "Access is denied.",
  scWin32Status_Hex =~ "8009030e", "SEC_E_NO_CREDENTIALS",
  scWin32Status_Hex =~ "8009030C", "SEC_E_LOGON_DENIED",
  "See - https://msdn.microsoft.com/library/cc231199.aspx")
  // decode URI when available
  | extend decodedUriQuery = url_decode(csUriQuery)
  // Count of failed attempts from same client IP
  | summarize makeset(decodedUriQuery), makeset(csUserName), makeset(sSiteName), makeset(sPort), makeset(csUserAgent), makeset(csMethod), makeset(csUriQuery), makeset(scStatusFull), makeset(scStatusFull_Friendly), makeset(scWin32Status_Hex), makeset(scWin32Status_Friendly), FailedConnectionsCount = count() by bin(TimeGenerated, timeBin), cIP, Computer, sIP
  | where FailedConnectionsCount >= failedThreshold
  | project TimeGenerated, cIP, set_csUserName, set_decodedUriQuery, Computer, set_sSiteName, sIP, set_sPort, set_csUserAgent, set_csMethod, set_scStatusFull, set_scStatusFull_Friendly, set_scWin32Status_Hex, set_scWin32Status_Friendly, FailedConnectionsCount
  | order by FailedConnectionsCount
  | extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
  | extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)  
triggerOperator: gt

ARM

{
  "$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/19e01883-15d8-4eb6-a7a5-3276cd668388')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/19e01883-15d8-4eb6-a7a5-3276cd668388')]",
      "properties": {
        "alertRuleTemplateName": "19e01883-15d8-4eb6-a7a5-3276cd668388",
        "customDetails": null,
        "description": "'Identifies when 20 or more failed attempts from a given client IP in 1 minute occur on the IIS server.\nThis could be indicative of an attempted brute force. This could also simply indicate a misconfigured service or device.\nRecommendations: Validate that these are expected connections from the given Client IP.  If the client IP is not recognized, potentially block these connections at the edge device.\nIf these are expected connections, verify the credentials are properly configured on the system, service, application or device that is associated with the client IP.\nReferences:\nIIS status code mapping: https://support.microsoft.com/help/943891/the-http-status-code-in-iis-7-0-iis-7-5-and-iis-8-0\nWin32 Status code mapping: https://msdn.microsoft.com/library/cc231199.aspx'\n",
        "displayName": "High count of failed attempts from same client IP",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "Computer",
                "identifier": "FullName"
              },
              {
                "columnName": "HostName",
                "identifier": "HostName"
              },
              {
                "columnName": "HostNameDomain",
                "identifier": "NTDomain"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "cIP",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Detections/W3CIISLog/HighFailedLogonCountByClientIP.yaml",
        "query": "let timeBin = 1m;\nlet failedThreshold = 20;\nW3CIISLog\n| where scStatus in (\"401\",\"403\")\n| where csUserName != \"-\"\n| extend scStatusFull = strcat(scStatus, \".\",scSubStatus)\n// Map common IIS codes\n| extend scStatusFull_Friendly = case(\nscStatusFull == \"401.0\", \"Access denied.\",\nscStatusFull == \"401.1\", \"Logon failed.\",\nscStatusFull == \"401.2\", \"Logon failed due to server configuration.\",\nscStatusFull == \"401.3\", \"Unauthorized due to ACL on resource.\",\nscStatusFull == \"401.4\", \"Authorization failed by filter.\",\nscStatusFull == \"401.5\", \"Authorization failed by ISAPI/CGI application.\",\nscStatusFull == \"403.0\", \"Forbidden.\",\nscStatusFull == \"403.4\", \"SSL required.\",\n\"See - https://support.microsoft.com/help/943891/the-http-status-code-in-iis-7-0-iis-7-5-and-iis-8-0\")\n// Mapping to Hex so can be mapped using website in comments above\n| extend scWin32Status_Hex = tohex(tolong(scWin32Status))\n// Map common win32 codes\n| extend scWin32Status_Friendly = case(\nscWin32Status_Hex =~ \"775\", \"The referenced account is currently locked out and cannot be logged on to.\",\nscWin32Status_Hex =~ \"52e\", \"Logon failure: Unknown user name or bad password.\",\nscWin32Status_Hex =~ \"532\", \"Logon failure: The specified account password has expired.\",\nscWin32Status_Hex =~ \"533\", \"Logon failure: Account currently disabled.\",\nscWin32Status_Hex =~ \"2ee2\", \"The request has timed out.\",\nscWin32Status_Hex =~ \"0\", \"The operation completed successfully.\",\nscWin32Status_Hex =~ \"1\", \"Incorrect function.\",\nscWin32Status_Hex =~ \"2\", \"The system cannot find the file specified.\",\nscWin32Status_Hex =~ \"3\", \"The system cannot find the path specified.\",\nscWin32Status_Hex =~ \"4\", \"The system cannot open the file.\",\nscWin32Status_Hex =~ \"5\", \"Access is denied.\",\nscWin32Status_Hex =~ \"8009030e\", \"SEC_E_NO_CREDENTIALS\",\nscWin32Status_Hex =~ \"8009030C\", \"SEC_E_LOGON_DENIED\",\n\"See - https://msdn.microsoft.com/library/cc231199.aspx\")\n// decode URI when available\n| extend decodedUriQuery = url_decode(csUriQuery)\n// Count of failed attempts from same client IP\n| summarize makeset(decodedUriQuery), makeset(csUserName), makeset(sSiteName), makeset(sPort), makeset(csUserAgent), makeset(csMethod), makeset(csUriQuery), makeset(scStatusFull), makeset(scStatusFull_Friendly), makeset(scWin32Status_Hex), makeset(scWin32Status_Friendly), FailedConnectionsCount = count() by bin(TimeGenerated, timeBin), cIP, Computer, sIP\n| where FailedConnectionsCount >= failedThreshold\n| project TimeGenerated, cIP, set_csUserName, set_decodedUriQuery, Computer, set_sSiteName, sIP, set_sPort, set_csUserAgent, set_csMethod, set_scStatusFull, set_scStatusFull_Friendly, set_scWin32Status_Hex, set_scWin32Status_Friendly, FailedConnectionsCount\n| order by FailedConnectionsCount\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": "Medium",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "CredentialAccess"
        ],
        "techniques": [
          "T1110"
        ],
        "templateVersion": "1.0.4",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}