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Detection rules › Kusto

Google DNS - CVE-2020-1350 (SIGRED) exploitation pattern

Severity
high
Time window
1m
Group by
SrcIpAddr
Source
github.com/Azure/Azure-Sentinel

'Detects exploitation pattern of CVE-2020-1350 (SIGRED) vulnerability.'

MITRE ATT&CK coverage

TacticTechniques
Privilege EscalationT1068 Exploitation for Privilege Escalation

Rule body kusto

id: 1267d53d-f5fd-418b-b8da-34453a5994c2
name: Google DNS - CVE-2020-1350 (SIGRED) exploitation pattern
description: |
  'Detects exploitation pattern of CVE-2020-1350 (SIGRED) vulnerability.'
severity: High
requiredDataConnectors:
  - connectorId: GCPDNSDataConnector
    dataTypes:
      - GCPCloudDNS
queryFrequency: 15m
queryPeriod: 15m
triggerOperator: gt
triggerThreshold: 0
tactics:
  - PrivilegeEscalation
relevantTechniques:
  - T1068
query: |
  let threshold = 15;
  GCPCloudDNS
  | where QueryTypeName in~ ('SIG', 'RRSIG')
  | where NetworkProtocol =~ 'TCP'
  | summarize count() by SrcIpAddr, bin(TimeGenerated, 1m)
  | where count_ < threshold
  | extend IPCustomEntity = SrcIpAddr
entityMappings:
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: IPCustomEntity
version: 1.0.0
kind: Scheduled

Stages and Predicates

Parameters

let threshold = 15;

Stage 1: source

GCPCloudDNS

Stage 2: where

| where QueryTypeName in~ ('SIG', 'RRSIG')

Stage 3: where

| where NetworkProtocol =~ 'TCP'

Stage 4: summarize

| summarize count() by SrcIpAddr, bin(TimeGenerated, 1m)

Stage 5: where

| where count_ < threshold

Stage 6: extend

| extend IPCustomEntity = SrcIpAddr

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
NetworkProtocoleq
  • TCP
QueryTypeNamein
  • RRSIG
  • SIG
count_lt
  • 15 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
SrcIpAddrsummarize
IPCustomEntityextend