Detection rules › Kusto

CYFIRMA - Medium Severity Asset based Vulnerabilities Rule Alert

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
Group by
name
Source
github.com/Azure/Azure-Sentinel

"This rule detects medium severity asset-based vulnerabilities from CYFIRMA's vulnerability intelligence data. It identifies vulnerabilities with a confidence score of 50 or higher, excluding those categorized as 'ATTACK_SURFACE_VULNERABILITY', and generates alerts for assets that may be at risk."

MITRE ATT&CK coverage

Rule body kusto

id: 6306f2d9-34a3-409a-850d-175b7bdd1ab1
name: CYFIRMA - Medium Severity Asset based Vulnerabilities Rule Alert
description: |
  "This rule detects medium severity asset-based vulnerabilities from CYFIRMA's vulnerability intelligence data. 
  It identifies vulnerabilities with a confidence score of 50 or higher, excluding those categorized as 'ATTACK_SURFACE_VULNERABILITY', and generates alerts for assets that may be at risk."
version: 1.0.1
kind: Scheduled
severity: Medium
enabled: false
requiredDataConnectors:
  - connectorId: CyfirmaVulnerabilitiesIntelDC
    dataTypes:
      - CyfirmaVulnerabilities_CL
query: |
  // Medium severity - Asset based Vulnerabilities
  let timeFrame= 5m;
  CyfirmaVulnerabilities_CL
  | 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 
      attack_complexity         = tostring(props.attack_complexity),
      cvss_score                = toreal(props.cvss_score),
      integrity_impact          = tostring(props.integrity_impact),
      impact_score              = tostring(props.impact_score),
      attack_vector             = tostring(props.attack_vector),
      privileges_required       = tostring(props.privileges_required),
      cvss_version              = tostring(props.cvss_version),
      user_interaction          = tostring(props.user_interaction),
      cvss_vector               = tostring(props.cvss_vector),
      scope                     = tostring(props.scope),
      confidentiality_impact    = tostring(props.confidentiality_impact),
      exploitability_score      = toreal(props.exploitability_score),
      products                  = tostring(props.products),
      technologies              = tostring(props.technologies),
      vendors                   = tostring(props.vendors),
      confidence_score          = toint(confidence),
      servers                   = tostring(props.servers),
      vulnerability_type        = tostring(props.vulnerability_type),
      vulnerability_category        = tostring(props.vulnerability_category),
      NetworkIPs                = tostring(props.ips),
      ProviderName              ='CYFIRMA',
      ProductName               ='DeCYFIR/DeTCT'
  | summarize arg_max(
                  integrity_impact,
                  TimeGenerated, 
                  id,
                  description,
                  confidence_score,
                  created,
                  modified,
                  attack_complexity,
                  cvss_score,
                  impact_score,
                  attack_vector,
                  privileges_required,
                  cvss_version,
                  user_interaction,
                  cvss_vector,
                  scope,
                  confidentiality_impact,
                  exploitability_score,
                  products,
                  technologies,
                  vendors,
                  ProviderName,
                  ProductName,
                  servers,
                  NetworkIPs,
                  vulnerability_type,
                  vulnerability_category
              )
      by name
  | where  confidence_score >= 60 and vulnerability_category != 'ATTACK_SURFACE_VULNERABILITY' and TimeGenerated between (ago(timeFrame) .. now())
  | project 
      TimeGenerated,
      name,
      confidence_score,
      integrity_impact,
      attack_complexity,
      cvss_score,
      impact_score,
      attack_vector,
      UID = id,
      description,
      created,
      modified,
      privileges_required,
      cvss_version,
      user_interaction,
      cvss_vector,
      scope,
      confidentiality_impact,
      exploitability_score,
      products,
      technologies,
      vendors,
      ProviderName,
      ProductName,
      servers,
      NetworkIPs,
      vulnerability_type,
      vulnerability_category
queryFrequency: 5m
queryPeriod: 5m
triggerOperator: GreaterThan
triggerThreshold: 0
suppressionDuration: 5m
suppressionEnabled: false
tactics:
  - Execution
  - LateralMovement
  - PrivilegeEscalation
  - InitialAccess
  - CredentialAccess
  - DefenseEvasion
relevantTechniques:
  - T1059
  - T1203
  - T1210
  - T1068
  - T1190
  - T1133
  - T1003
  - T1553
  - T1548.002
  - T1021.002
alertDetailsOverride:
alertDisplayNameFormat: "CYFIRMA - Medium Severity Asset based Vulnerability Identified - {{name}} "
alertDescriptionFormat: "{{description}} "
alertDynamicProperties:
  - alertProperty: ProductName
    value: ProductName
  - alertProperty: ProviderName
    value: ProviderName
customDetails:
  TimeGenerated: TimeGenerated
  CVE: name
  ConfidenceScore: confidence_score
  IntegrityImpact: integrity_impact
  AttackComplexity: attack_complexity
  CVSSScore: cvss_score
  ImpactScore: impact_score
  AttackVector: attack_vector
  ConfidentialImpact: confidentiality_impact
  PrivilegesRequired: privileges_required
  CVSSVersion: cvss_version
  UserInteraction: user_interaction
  CVSSVector: cvss_vector
  scope: scope
  ExploitabilityScore: exploitability_score
  Modified: modified
  Products: products
  Vendors: vendors
  Technologies: technologies
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

CyfirmaVulnerabilities_CL

Stage 2: extend

| extend parsed = parse_json(extensions)

Stage 3: extend

| 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 
    attack_complexity         = tostring(props.attack_complexity),
    cvss_score                = toreal(props.cvss_score),
    integrity_impact          = tostring(props.integrity_impact),
    impact_score              = tostring(props.impact_score),
    attack_vector             = tostring(props.attack_vector),
    privileges_required       = tostring(props.privileges_required),
    cvss_version              = tostring(props.cvss_version),
    user_interaction          = tostring(props.user_interaction),
    cvss_vector               = tostring(props.cvss_vector),
    scope                     = tostring(props.scope),
    confidentiality_impact    = tostring(props.confidentiality_impact),
    exploitability_score      = toreal(props.exploitability_score),
    products                  = tostring(props.products),
    technologies              = tostring(props.technologies),
    vendors                   = tostring(props.vendors),
    confidence_score          = toint(confidence),
    servers                   = tostring(props.servers),
    vulnerability_type        = tostring(props.vulnerability_type),
    vulnerability_category        = tostring(props.vulnerability_category),
    NetworkIPs                = tostring(props.ips),
    ProviderName              ='CYFIRMA',
    ProductName               ='DeCYFIR/DeTCT'

Stage 6: summarize

| summarize arg_max(
                integrity_impact,
                TimeGenerated, 
                id,
                description,
                confidence_score,
                created,
                modified,
                attack_complexity,
                cvss_score,
                impact_score,
                attack_vector,
                privileges_required,
                cvss_version,
                user_interaction,
                cvss_vector,
                scope,
                confidentiality_impact,
                exploitability_score,
                products,
                technologies,
                vendors,
                ProviderName,
                ProductName,
                servers,
                NetworkIPs,
                vulnerability_type,
                vulnerability_category
            )
    by name

Stage 7: where

| where  confidence_score >= 60 and vulnerability_category != 'ATTACK_SURFACE_VULNERABILITY' and TimeGenerated between (ago(timeFrame) .. now())

Stage 8: project

| project 
    TimeGenerated,
    name,
    confidence_score,
    integrity_impact,
    attack_complexity,
    cvss_score,
    impact_score,
    attack_vector,
    UID = id,
    description,
    created,
    modified,
    privileges_required,
    cvss_version,
    user_interaction,
    cvss_vector,
    scope,
    confidentiality_impact,
    exploitability_score,
    products,
    technologies,
    vendors,
    ProviderName,
    ProductName,
    servers,
    NetworkIPs,
    vulnerability_type,
    vulnerability_category

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
confidence_scorege
  • 60 transforms: cased
vulnerability_categoryne
  • ATTACK_SURFACE_VULNERABILITY transforms: cased

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
NetworkIPsproject
ProductNameproject
ProviderNameproject
TimeGeneratedproject
UIDproject
attack_complexityproject
attack_vectorproject
confidence_scoreproject
confidentiality_impactproject
createdproject
cvss_scoreproject
cvss_vectorproject
cvss_versionproject
descriptionproject
exploitability_scoreproject
impact_scoreproject
integrity_impactproject
modifiedproject
nameproject
privileges_requiredproject
productsproject
scopeproject
serversproject
technologiesproject
user_interactionproject
vendorsproject
vulnerability_categoryproject
vulnerability_typeproject