Cisco ASA - average attack detection rate increase

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Id	79f29feb-6a9d-4cdf-baaa-2daf480a5da1
Rulename	Cisco ASA - average attack detection rate increase
Description	This will help you determine if Cisco ASA devices are under heavier attack than normal over the last hour versus the previous 6 hours based on DeviceEventClassID 733100 References: https://www.cisco.com/c/en/us/td/docs/security/asa/syslog/b_syslog/syslogs9.html Details on how to further troubleshoot/investigate: https://www.cisco.com/c/en/us/support/docs/security/asa-5500-x-series-next-generation-firewalls/113685-asa-threat-detection.html
Severity	Low
Tactics	Discovery Impact
Techniques	T1046 T1498
Required data connectors	CiscoASA
Kind	Scheduled
Query frequency	1h
Query period	6h
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/CiscoASA/Analytic Rules/CiscoASA-AvgAttackDetectRateIncrease.yaml
Version	1.0.2
Arm template	79f29feb-6a9d-4cdf-baaa-2daf480a5da1.json

KQL

let timeframe = 1h;
let last1h = CommonSecurityLog
| where TimeGenerated >= ago(timeframe)
| where isempty(CommunicationDirection)
| where DeviceEventClassID == "733100"
| extend SourceOfDropRateCount = tostring(split(tostring(split(Message, "]")[0]),"[ ")[1])
| extend splitMessage = split(Message, ".")
| extend DropRate = tostring(split(tostring(splitMessage[0]),"] ")[1])
| extend CurrentBurstRate = split(tostring(split(tostring(splitMessage[1]),"  ")[0]),"is ")
| extend CurrentBurstRatePerSec = toint(split(tostring(CurrentBurstRate[1])," ")[0])
| extend MaxConfiguredBurstRate = toint(CurrentBurstRate[2])
| extend CurrentAvgRate = split(tostring(split(tostring(splitMessage[1]),"  ")[1]),"is ")
| extend CurrentAvgRatePerSec = toint(split(tostring(CurrentAvgRate[1])," ")[0])
| extend MaxConfiguredAvgRate = toint(CurrentAvgRate[2])
| extend CumulativeTotal = toint(split(tostring(split(tostring(splitMessage[1]),"  ")[2]),"is ")[1])
| summarize last1hCumTotal = sum(CumulativeTotal), last1hAvgRatePerSec = avg(CurrentAvgRatePerSec), last1hAvgBurstRatePerSec = avg(CurrentBurstRatePerSec) by DeviceName, DeviceEventClassID, SourceIP, SourceOfDropRateCount, DropRate;
let prev6h = CommonSecurityLog
| where TimeGenerated between (ago(6h) .. ago(1h))
| where isempty(CommunicationDirection)
| where DeviceEventClassID == "733100"
| extend SourceOfDropRateCount = tostring(split(tostring(split(Message, "]")[0]),"[ ")[1])
| extend splitMessage = split(Message, ".")
| extend DropRate = tostring(split(tostring(splitMessage[0]),"] ")[1])
| extend CurrentBurstRate = split(tostring(split(tostring(splitMessage[1]),"  ")[0]),"is ")
| extend prevCurrentBurstRatePerSec = toint(split(tostring(CurrentBurstRate[1])," ")[0])
| extend prevMaxConfiguredBurstRate = toint(CurrentBurstRate[2])
| extend CurrentAvgRate = split(tostring(split(tostring(splitMessage[1]),"  ")[1]),"is ")
| extend prevCurrentAvgRatePerSec = toint(split(tostring(CurrentAvgRate[1])," ")[0])
| extend prevMaxConfiguredAvgRate = toint(CurrentAvgRate[2])
| extend prevCumulativeTotal = toint(split(tostring(split(tostring(splitMessage[1]),"  ")[2]),"is ")[1])
| summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), prev6hCumTotal = sum(prevCumulativeTotal), prev6hAvgRatePerSec = avg(prevCurrentAvgRatePerSec), prev6hAvgBurstRatePerSec = avg(prevCurrentBurstRatePerSec)
by DeviceName, DeviceEventClassID, SourceIP, SourceOfDropRateCount, DropRate;
last1h | join (
  prev6h
) on DeviceName, DeviceEventClassID, SourceIP, SourceOfDropRateCount, DropRate
| project StartTimeUtc, EndTimeUtc, DeviceName, DeviceEventClassID, SourceIP, SourceOfDropRateCount, DropRate, last1hCumTotal, prev6hCumTotal, prev6hAvgCumTotal = prev6hCumTotal/6, last1hAvgRatePerSec, prev6hAvgRatePerSec, last1hAvgBurstRatePerSec, prev6hAvgBurstRatePerSec
// Select only events that indicate a doubling of the expected rate in the last hour over the previous 6 hours
| where last1hCumTotal > 2*prev6hAvgCumTotal or last1hAvgRatePerSec > 2*prev6hAvgRatePerSec or last1hAvgBurstRatePerSec > 2*prev6hAvgBurstRatePerSec
| extend HostName = tostring(split(DeviceName, ".")[0]), DomainIndex = toint(indexof(DeviceName, '.'))
| extend HostNameDomain = iff(DomainIndex != -1, substring(DeviceName, DomainIndex + 1), DeviceName)

YAML

relevantTechniques:
- T1046
- T1498
name: Cisco ASA - average attack detection rate increase
requiredDataConnectors:
- dataTypes:
  - CommonSecurityLog
  connectorId: CiscoASA
entityMappings:
- fieldMappings:
  - identifier: FullName
    columnName: DeviceName
  - identifier: HostName
    columnName: HostName
  - identifier: DnsDomain
    columnName: HostNameDomain
  entityType: Host
- fieldMappings:
  - identifier: Address
    columnName: SourceIP
  entityType: IP
triggerThreshold: 0
id: 79f29feb-6a9d-4cdf-baaa-2daf480a5da1
tactics:
- Discovery
- Impact
version: 1.0.2
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/CiscoASA/Analytic Rules/CiscoASA-AvgAttackDetectRateIncrease.yaml
queryPeriod: 6h
kind: Scheduled
queryFrequency: 1h
severity: Low
status: Available
description: |
  'This will help you determine if Cisco ASA devices are under heavier attack than normal over the last hour versus the previous 6 hours based on DeviceEventClassID 733100
  References: https://www.cisco.com/c/en/us/td/docs/security/asa/syslog/b_syslog/syslogs9.html
  Details on how to further troubleshoot/investigate: https://www.cisco.com/c/en/us/support/docs/security/asa-5500-x-series-next-generation-firewalls/113685-asa-threat-detection.html'  
query: |
  let timeframe = 1h;
  let last1h = CommonSecurityLog
  | where TimeGenerated >= ago(timeframe)
  | where isempty(CommunicationDirection)
  | where DeviceEventClassID == "733100"
  | extend SourceOfDropRateCount = tostring(split(tostring(split(Message, "]")[0]),"[ ")[1])
  | extend splitMessage = split(Message, ".")
  | extend DropRate = tostring(split(tostring(splitMessage[0]),"] ")[1])
  | extend CurrentBurstRate = split(tostring(split(tostring(splitMessage[1]),"  ")[0]),"is ")
  | extend CurrentBurstRatePerSec = toint(split(tostring(CurrentBurstRate[1])," ")[0])
  | extend MaxConfiguredBurstRate = toint(CurrentBurstRate[2])
  | extend CurrentAvgRate = split(tostring(split(tostring(splitMessage[1]),"  ")[1]),"is ")
  | extend CurrentAvgRatePerSec = toint(split(tostring(CurrentAvgRate[1])," ")[0])
  | extend MaxConfiguredAvgRate = toint(CurrentAvgRate[2])
  | extend CumulativeTotal = toint(split(tostring(split(tostring(splitMessage[1]),"  ")[2]),"is ")[1])
  | summarize last1hCumTotal = sum(CumulativeTotal), last1hAvgRatePerSec = avg(CurrentAvgRatePerSec), last1hAvgBurstRatePerSec = avg(CurrentBurstRatePerSec) by DeviceName, DeviceEventClassID, SourceIP, SourceOfDropRateCount, DropRate;
  let prev6h = CommonSecurityLog
  | where TimeGenerated between (ago(6h) .. ago(1h))
  | where isempty(CommunicationDirection)
  | where DeviceEventClassID == "733100"
  | extend SourceOfDropRateCount = tostring(split(tostring(split(Message, "]")[0]),"[ ")[1])
  | extend splitMessage = split(Message, ".")
  | extend DropRate = tostring(split(tostring(splitMessage[0]),"] ")[1])
  | extend CurrentBurstRate = split(tostring(split(tostring(splitMessage[1]),"  ")[0]),"is ")
  | extend prevCurrentBurstRatePerSec = toint(split(tostring(CurrentBurstRate[1])," ")[0])
  | extend prevMaxConfiguredBurstRate = toint(CurrentBurstRate[2])
  | extend CurrentAvgRate = split(tostring(split(tostring(splitMessage[1]),"  ")[1]),"is ")
  | extend prevCurrentAvgRatePerSec = toint(split(tostring(CurrentAvgRate[1])," ")[0])
  | extend prevMaxConfiguredAvgRate = toint(CurrentAvgRate[2])
  | extend prevCumulativeTotal = toint(split(tostring(split(tostring(splitMessage[1]),"  ")[2]),"is ")[1])
  | summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), prev6hCumTotal = sum(prevCumulativeTotal), prev6hAvgRatePerSec = avg(prevCurrentAvgRatePerSec), prev6hAvgBurstRatePerSec = avg(prevCurrentBurstRatePerSec)
  by DeviceName, DeviceEventClassID, SourceIP, SourceOfDropRateCount, DropRate;
  last1h | join (
    prev6h
  ) on DeviceName, DeviceEventClassID, SourceIP, SourceOfDropRateCount, DropRate
  | project StartTimeUtc, EndTimeUtc, DeviceName, DeviceEventClassID, SourceIP, SourceOfDropRateCount, DropRate, last1hCumTotal, prev6hCumTotal, prev6hAvgCumTotal = prev6hCumTotal/6, last1hAvgRatePerSec, prev6hAvgRatePerSec, last1hAvgBurstRatePerSec, prev6hAvgBurstRatePerSec
  // Select only events that indicate a doubling of the expected rate in the last hour over the previous 6 hours
  | where last1hCumTotal > 2*prev6hAvgCumTotal or last1hAvgRatePerSec > 2*prev6hAvgRatePerSec or last1hAvgBurstRatePerSec > 2*prev6hAvgBurstRatePerSec
  | extend HostName = tostring(split(DeviceName, ".")[0]), DomainIndex = toint(indexof(DeviceName, '.'))
  | extend HostNameDomain = iff(DomainIndex != -1, substring(DeviceName, DomainIndex + 1), DeviceName)  
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/79f29feb-6a9d-4cdf-baaa-2daf480a5da1')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/79f29feb-6a9d-4cdf-baaa-2daf480a5da1')]",
      "properties": {
        "alertRuleTemplateName": "79f29feb-6a9d-4cdf-baaa-2daf480a5da1",
        "customDetails": null,
        "description": "'This will help you determine if Cisco ASA devices are under heavier attack than normal over the last hour versus the previous 6 hours based on DeviceEventClassID 733100\nReferences: https://www.cisco.com/c/en/us/td/docs/security/asa/syslog/b_syslog/syslogs9.html\nDetails on how to further troubleshoot/investigate: https://www.cisco.com/c/en/us/support/docs/security/asa-5500-x-series-next-generation-firewalls/113685-asa-threat-detection.html'\n",
        "displayName": "Cisco ASA - average attack detection rate increase",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "DeviceName",
                "identifier": "FullName"
              },
              {
                "columnName": "HostName",
                "identifier": "HostName"
              },
              {
                "columnName": "HostNameDomain",
                "identifier": "DnsDomain"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "SourceIP",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/CiscoASA/Analytic Rules/CiscoASA-AvgAttackDetectRateIncrease.yaml",
        "query": "let timeframe = 1h;\nlet last1h = CommonSecurityLog\n| where TimeGenerated >= ago(timeframe)\n| where isempty(CommunicationDirection)\n| where DeviceEventClassID == \"733100\"\n| extend SourceOfDropRateCount = tostring(split(tostring(split(Message, \"]\")[0]),\"[ \")[1])\n| extend splitMessage = split(Message, \".\")\n| extend DropRate = tostring(split(tostring(splitMessage[0]),\"] \")[1])\n| extend CurrentBurstRate = split(tostring(split(tostring(splitMessage[1]),\"  \")[0]),\"is \")\n| extend CurrentBurstRatePerSec = toint(split(tostring(CurrentBurstRate[1]),\" \")[0])\n| extend MaxConfiguredBurstRate = toint(CurrentBurstRate[2])\n| extend CurrentAvgRate = split(tostring(split(tostring(splitMessage[1]),\"  \")[1]),\"is \")\n| extend CurrentAvgRatePerSec = toint(split(tostring(CurrentAvgRate[1]),\" \")[0])\n| extend MaxConfiguredAvgRate = toint(CurrentAvgRate[2])\n| extend CumulativeTotal = toint(split(tostring(split(tostring(splitMessage[1]),\"  \")[2]),\"is \")[1])\n| summarize last1hCumTotal = sum(CumulativeTotal), last1hAvgRatePerSec = avg(CurrentAvgRatePerSec), last1hAvgBurstRatePerSec = avg(CurrentBurstRatePerSec) by DeviceName, DeviceEventClassID, SourceIP, SourceOfDropRateCount, DropRate;\nlet prev6h = CommonSecurityLog\n| where TimeGenerated between (ago(6h) .. ago(1h))\n| where isempty(CommunicationDirection)\n| where DeviceEventClassID == \"733100\"\n| extend SourceOfDropRateCount = tostring(split(tostring(split(Message, \"]\")[0]),\"[ \")[1])\n| extend splitMessage = split(Message, \".\")\n| extend DropRate = tostring(split(tostring(splitMessage[0]),\"] \")[1])\n| extend CurrentBurstRate = split(tostring(split(tostring(splitMessage[1]),\"  \")[0]),\"is \")\n| extend prevCurrentBurstRatePerSec = toint(split(tostring(CurrentBurstRate[1]),\" \")[0])\n| extend prevMaxConfiguredBurstRate = toint(CurrentBurstRate[2])\n| extend CurrentAvgRate = split(tostring(split(tostring(splitMessage[1]),\"  \")[1]),\"is \")\n| extend prevCurrentAvgRatePerSec = toint(split(tostring(CurrentAvgRate[1]),\" \")[0])\n| extend prevMaxConfiguredAvgRate = toint(CurrentAvgRate[2])\n| extend prevCumulativeTotal = toint(split(tostring(split(tostring(splitMessage[1]),\"  \")[2]),\"is \")[1])\n| summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), prev6hCumTotal = sum(prevCumulativeTotal), prev6hAvgRatePerSec = avg(prevCurrentAvgRatePerSec), prev6hAvgBurstRatePerSec = avg(prevCurrentBurstRatePerSec)\nby DeviceName, DeviceEventClassID, SourceIP, SourceOfDropRateCount, DropRate;\nlast1h | join (\n  prev6h\n) on DeviceName, DeviceEventClassID, SourceIP, SourceOfDropRateCount, DropRate\n| project StartTimeUtc, EndTimeUtc, DeviceName, DeviceEventClassID, SourceIP, SourceOfDropRateCount, DropRate, last1hCumTotal, prev6hCumTotal, prev6hAvgCumTotal = prev6hCumTotal/6, last1hAvgRatePerSec, prev6hAvgRatePerSec, last1hAvgBurstRatePerSec, prev6hAvgBurstRatePerSec\n// Select only events that indicate a doubling of the expected rate in the last hour over the previous 6 hours\n| where last1hCumTotal > 2*prev6hAvgCumTotal or last1hAvgRatePerSec > 2*prev6hAvgRatePerSec or last1hAvgBurstRatePerSec > 2*prev6hAvgBurstRatePerSec\n| extend HostName = tostring(split(DeviceName, \".\")[0]), DomainIndex = toint(indexof(DeviceName, '.'))\n| extend HostNameDomain = iff(DomainIndex != -1, substring(DeviceName, DomainIndex + 1), DeviceName)\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT6H",
        "severity": "Low",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Discovery",
          "Impact"
        ],
        "techniques": [
          "T1046",
          "T1498"
        ],
        "templateVersion": "1.0.2",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}