Detection rules › Kusto

CYFIRMA - Medium severity Malicious Network Indicators with Block Action Rule

This is a third-party alert feed, not a detection over modeled telemetry. The vendor product raised the finding; this rule forwards it into the SIEM. It is searchable for reference but is excluded from the detection-rule browse and the ATT&CK coverage matrix.

Severity
medium
Time window
5m
Source
github.com/Azure/Azure-Sentinel

"This rule detects network-based indicators such as IP addresses, domains, and URLs reported by CYFIRMA threat intelligence with a recommended action of 'Block' and no specified role. These indicators may be associated with infrastructure used in phishing campaigns, malware, or initial access via watering hole or drive-by compromise techniques."

MITRE ATT&CK coverage

Rule body kusto

id: 4e7d1851-5aab-478d-b348-4b83dc2b03d9
name: CYFIRMA - Medium severity Malicious Network Indicators with Block Action Rule
description: |
  "This rule detects network-based indicators such as IP addresses, domains, and URLs reported by CYFIRMA threat intelligence with a recommended action of 'Block' and no specified role. 
  These indicators may be associated with infrastructure used in phishing campaigns, malware, or initial access via watering hole or drive-by compromise techniques."
version: 1.0.1
kind: Scheduled
severity: Medium
enabled: false
requiredDataConnectors:
  - connectorId: CyfirmaCyberIntelligenceDC
    dataTypes:
      - CyfirmaIndicators_CL
query: |
  // Network Indicators with Block Action Rule
  let timeFrame= 5m;
  CyfirmaIndicators_CL 
  | where  (ConfidenceScore < 80 and ConfidenceScore >= 50)
      and TimeGenerated between (ago(timeFrame) .. now())
      and pattern !contains 'file:hashes' and RecommendedActions has 'Block' and (isempty(Roles) or not(Roles has_any ('Command & Control', 'Malware', 'TOR', 'Trojan', 'Phishing')))
  | extend IPv4 = extract(@"ipv4-addr:value\s*=\s*'([^']+)'", 1, pattern)
  | extend IPv6 = extract(@"ipv6-addr:value\s*=\s*'([^']+)'", 1, pattern)
  | extend URL = extract(@"url:value\s*=\s*'([^']+)'", 1, pattern)
  | extend Domain = extract(@"domain-name:value\s*=\s*'([^']+)'", 1, pattern)
  | extend parsed = parse_json(extensions)
  | extend extensionKeys = bag_keys(parsed)
  | mv-expand extensionKeys
  | extend extensionKeyStr = tostring(extensionKeys)
  | extend ext = parsed[extensionKeyStr]
  | extend props = ext.properties
  | extend 
      extension_id = extensionKeyStr,
      ASN_Owner = props.asn_owner,
      ASN = props.asn,
      ProviderName = 'CYFIRMA',
      ProductName = 'DeCYFIR/DeTCT'
  | project
      IPv4,
      IPv6,
      URL,
      Domain,
      ThreatActors,
      RecommendedActions,
      Sources,
      Roles,
      Country,
      IPAbuse,
      name,
      Description,
      ConfidenceScore,
      IndicatorID,
      created,
      modified,
      valid_from,
      Tags,
      ThreatType,
      TimeGenerated,
      SecurityVendors,
      ProductName,
      ProviderName
queryFrequency: 5m
queryPeriod: 5m
triggerOperator: GreaterThan
triggerThreshold: 0
suppressionDuration: 5m
suppressionEnabled: true
tactics:
  - InitialAccess
  - Execution
  - Reconnaissance
  - Impact
relevantTechniques:
  - T1566
  - T1189
  - T1204
  - T1595
  - T1498
  - T1566.002
  - T1204.001
  - T1595.002
alertDetailsOverride:
  alertDisplayNameFormat: "High-Confidence Malicious Network Indicators with Block Action Rule - {{name}} "
  alertDescriptionFormat: "{{Description}} - {{name}} "
  alertDynamicProperties:
    - alertProperty: ProductName
      value: ProductName
    - alertProperty: ProviderName
      value: ProviderName
customDetails:
  ThreatActors: ThreatActors
  Sources: Sources
  RecommendedActions: RecommendedActions
  Roles: Roles
  Country: Country
  Description: Description
  ConfidenceScore: ConfidenceScore
  SecurityVendors: SecurityVendors
  IndicatorID: IndicatorID
  Created: created
  Modified: modified
  ValidFrom: valid_from
  Tags: Tags
  ThreatType: ThreatType
  TimeGenerated: TimeGenerated
  IPAbuse: IPAbuse
entityMappings:
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: IPv4
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: IPv6
  - entityType: DNS
    fieldMappings:
      - identifier: DomainName
        columnName: Domain
  - entityType: URL
    fieldMappings:
      - identifier: Url
        columnName: URL
incidentConfiguration:
  createIncident: true
  groupingConfiguration:
    enabled: false
    reopenClosedIncident: false
    lookbackDuration: PT5H
    matchingMethod: AllEntities
eventGroupingSettings:
  aggregationKind: AlertPerResult

Stages and Predicates

Parameters

let timeFrame = 5m;

Stage 1: source

CyfirmaIndicators_CL

Stage 2: where

| where  (ConfidenceScore < 80 and ConfidenceScore >= 50)
    and TimeGenerated between (ago(timeFrame) .. now())
    and pattern !contains 'file:hashes' and RecommendedActions has 'Block' and (isempty(Roles) or not(Roles has_any ('Command & Control', 'Malware', 'TOR', 'Trojan', 'Phishing')))

Stage 3: extend (6 consecutive steps)

| extend IPv4 = extract(@"ipv4-addr:value\s*=\s*'([^']+)'", 1, pattern)
| extend IPv6 = extract(@"ipv6-addr:value\s*=\s*'([^']+)'", 1, pattern)
| extend URL = extract(@"url:value\s*=\s*'([^']+)'", 1, pattern)
| extend Domain = extract(@"domain-name:value\s*=\s*'([^']+)'", 1, pattern)
| extend parsed = parse_json(extensions)
| extend extensionKeys = bag_keys(parsed)

Stage 4: mv-expand

| mv-expand extensionKeys

Stage 5: extend (4 consecutive steps)

| extend extensionKeyStr = tostring(extensionKeys)
| extend ext = parsed[extensionKeyStr]
| extend props = ext.properties
| extend 
    extension_id = extensionKeyStr,
    ASN_Owner = props.asn_owner,
    ASN = props.asn,
    ProviderName = 'CYFIRMA',
    ProductName = 'DeCYFIR/DeTCT'

Stage 6: project

| project
    IPv4,
    IPv6,
    URL,
    Domain,
    ThreatActors,
    RecommendedActions,
    Sources,
    Roles,
    Country,
    IPAbuse,
    name,
    Description,
    ConfidenceScore,
    IndicatorID,
    created,
    modified,
    valid_from,
    Tags,
    ThreatType,
    TimeGenerated,
    SecurityVendors,
    ProductName,
    ProviderName

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

FieldKindExcluded values
patterncontainsfile:hashes

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
ConfidenceScorege
  • 50 transforms: cased
ConfidenceScorelt
  • 80 transforms: cased
RecommendedActionsmatch
  • Block transforms: term
Rolesis_null
  • (no value, null check)

Output fields

Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.

FieldSource
ConfidenceScoreproject
Countryproject
Descriptionproject
Domainproject
IPAbuseproject
IPv4project
IPv6project
IndicatorIDproject
ProductNameproject
ProviderNameproject
RecommendedActionsproject
Rolesproject
SecurityVendorsproject
Sourcesproject
Tagsproject
ThreatActorsproject
ThreatTypeproject
TimeGeneratedproject
URLproject
createdproject
modifiedproject
nameproject
valid_fromproject