↳ GitHub sourceAnalytics ruleMedium

CYFIRMA - Attack Surface - Weak Certificate Exposure - Medium Rule

Description

'This alert indicates that a weak or insecure SSL/TLS certificate has been detected on a public-facing asset monitored by Cyfirma. Such certificates do not meet modern encryption standards and are considered insecure, especially for handling sensitive transactions. This exposure increases the risk of man-in-the-middle attacks and loss of data integrity or confidentiality. Immediate remediation is advised by replacing weak certificates with strong, industry-compliant ones.'

Rule type: Scheduled
Version: 1.0.1
Declared status: Available
Query frequency: 5m
Query period: 5m
Trigger: gt 0

Declared MITRE coverage

Declared sources

Metadata from the source file. No dependencies inferred from KQL.

Connectors

CyfirmaAttackSurfaceAlertsConnector

Data types

CyfirmaASCertificatesAlerts_CL

KQL query

Original query, unchanged.

// Medium Severity Weak Certificate Exposure Detected
let timeFrame = 5m;
CyfirmaASCertificatesAlerts_CL
| where severity == 'High' and TimeGenerated between (ago(timeFrame) .. now())
| extend
    Description=description,
    FirstSeen=first_seen,
    LastSeen=last_seen,
    ValidFrom=valid_from,
    ValidTo=valid_to,
    RiskScore=risk_score,
    Domain=sub_domain,
    TopDomain=top_domain,
    Protocols=protocols,
    SelfSigned=self_signed,
    AlertUID=alert_uid,
    UID=uid,
    CertificateData= cert_data,
    CertificateHash=cert_hash,
    IssuedBy=issued_by,
    IssuedTo=issued_to,
    ProviderName='CYFIRMA',
    ProductName='DeCYFIR/DeTCT'
| project
    TimeGenerated,
    Description,
    Domain,
    TopDomain,
    RiskScore,
    FirstSeen,
    LastSeen,
    ValidFrom,
    ValidTo,
    Protocols,
    SelfSigned,
    CertificateData,
    CertificateHash,
    IssuedBy,
    IssuedTo,
    ProviderName,
    ProductName

Declared entities

DNSHost

Source provenance

GitHub

Displayed values come from files in Azure/Azure-Sentinel. They describe the published template, not your workspace configuration.

File: Solutions/Cyfirma Attack Surface/Analytic Rules/ASCertificatesMediumRule.yaml ↗
Commit: 9800e51 ↗
Source identifier: 5a617ff2-3e3d-44e7-b761-9f0d542ae191

Additional source files 2

Solutions/Cyfirma Attack Surface/Analytic Rules/ASCertificatesMediumRule.yamlsource ↗Solutions/Cyfirma Attack Surface/Data/Solution_CyfirmaASAlerts.jsonsolution-membership ↗

GSTEP / CATALOG TRACKING

Added to catalog : 16 Sept 2026 · 05:49 UTC
Last change observed : 16 Sept 2026 · 05:49 UTC

GSTEP sync dates, separate from the source content’s publication dates.