Detections/CommonSecurityLog/TimeSeriesAnomaly-MultiVendor_NetworkTraffic.yaml

id: 06a9b845-6a95-4432-a78b-83919b28c375
name: Time series anomaly detection for total volume of traffic
description: |
  'Identifies anamalous spikes in network traffic logs as compared to baseline or normal historical patterns.
  The query leverages a KQL built-in anomaly detection algorithm to find large deviations from baseline patterns.
  Sudden increases in network traffic volume may be an indication of data exfiltration attempts and should be investigated.
  The higher the score, the further it is from the baseline value.
  The output is aggregated to provide summary view of unique source IP to destination IP address and port traffic observed in the flagged anomaly hour.
  The source IP addresses which were sending less than percentotalthreshold of the total traffic have been exluded whose value can be adjusted as needed .
  You may have to run queries for individual source IP addresses from SourceIPlist to determine if anything looks suspicious'
severity: Medium
requiredDataConnectors:
  - connectorId: Barracuda
    dataTypes:
      - CommonSecurityLog
  - connectorId: CEF
    dataTypes:
      - CommonSecurityLog
  - connectorId: CheckPoint
    dataTypes:
      - CommonSecurityLog
  - connectorId: CiscoASA
    dataTypes:
      - CommonSecurityLog
  - connectorId: F5
    dataTypes:
      - CommonSecurityLog
  - connectorId: Fortinet
    dataTypes:
      - CommonSecurityLog
  - connectorId: PaloAltoNetworks
    dataTypes:
      - CommonSecurityLog
queryFrequency: 1d
queryPeriod: 14d
triggerOperator: gt
triggerThreshold: 3
tactics:
  - Exfiltration
relevantTechniques:
  - T1030
query: |
  let starttime = 14d;
  let endtime = 1d;
  let timeframe = 1h;
  let scorethreshold = 5;
  let percentotalthreshold = 50;
  let TimeSeriesData = CommonSecurityLog
  | where isnotempty(DestinationIP) and isnotempty(SourceIP)
  | where TimeGenerated between (startofday(ago(starttime))..startofday(ago(endtime)))
  | project TimeGenerated,SourceIP, DestinationIP, DeviceVendor
  | make-series Total=count() on TimeGenerated from startofday(ago(starttime)) to startofday(ago(endtime)) step timeframe by DeviceVendor;
  // Filtering specific records associated with spikes as outliers
  let TimeSeriesAlerts=materialize(TimeSeriesData
  | extend (anomalies, score, baseline) = series_decompose_anomalies(Total, scorethreshold, -1, 'linefit')
  | mv-expand Total to typeof(double), TimeGenerated to typeof(datetime), anomalies to typeof(double),score to typeof(double), baseline to typeof(long)
  | where anomalies > 0 | extend score = round(score,2), AnomalyHour = TimeGenerated
  | project DeviceVendor,AnomalyHour, TimeGenerated, Total, baseline, anomalies, score);
  let AnomalyHours = materialize(TimeSeriesAlerts  | where TimeGenerated > ago(2d) | project TimeGenerated);
  // Join anomalies with Base Data to popalate associated records for investigation - Results sorted by score in descending order
  TimeSeriesAlerts
  | where TimeGenerated > ago(2d)
  | join (
      CommonSecurityLog
  | where isnotempty(DestinationIP) and isnotempty(SourceIP)
  | where TimeGenerated > ago(2d)
  | extend DateHour = bin(TimeGenerated, 1h) // create a new column and round to hour
  | where DateHour in ((AnomalyHours)) //filter the dataset to only selected anomaly hours
  | summarize HourlyCount = count(), TimeGeneratedMax = arg_max(TimeGenerated, *), DestinationIPlist = make_set(DestinationIP, 100), DestinationPortlist = make_set(DestinationPort, 100) by DeviceVendor, SourceIP, TimeGeneratedHour= bin(TimeGenerated, 1h)
  | extend AnomalyHour = TimeGeneratedHour
  ) on AnomalyHour, DeviceVendor
  | extend PercentTotal = round((HourlyCount / Total) * 100, 3)
  | where PercentTotal > percentotalthreshold
  | project DeviceVendor , AnomalyHour, TimeGeneratedMax, SourceIP, DestinationIPlist, DestinationPortlist, HourlyCount, PercentTotal, Total, baseline, score, anomalies
  | summarize HourlyCount=sum(HourlyCount), StartTimeUtc=min(TimeGeneratedMax), EndTimeUtc=max(TimeGeneratedMax), SourceIPlist = make_set(SourceIP, 100), SourceIPMax= arg_max(SourceIP, *), DestinationIPlist = make_set(DestinationIPlist, 100), DestinationPortlist = make_set(DestinationPortlist, 100) by DeviceVendor , AnomalyHour, Total, baseline, score, anomalies
  | project DeviceVendor , AnomalyHour, EndTimeUtc, SourceIPMax ,SourceIPlist, DestinationIPlist, DestinationPortlist, HourlyCount, Total, baseline, score, anomalies

entityMappings:
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: SourceIPMax
version: 1.0.4
kind: Scheduled
metadata:
    source:
        kind: Community
    author:
        name: Microsoft Security Research
    support:
        tier: Community
    categories:
        domains: [ "Security - Others" ]