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CTE - Sudden Block Spike Detected

Description

A sudden spike in blocked URLs/domains on a single device may indicate an active phishing or malware campaign.
Rule type
Scheduled
Version
1.0.0
Query frequency
10m
Query period
10m
Trigger
gt 0

Declared MITRE coverage

Declared sources

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

Connectors

Data types

KQL query

Original query, unchanged.

CybereinforceCTE_CL
| where EventType == "block.url"
| extend d = parse_json(Details)
| extend
    DeviceId = tostring(d.deviceId),
    HostName = iff(isnotempty(tostring(d.hostname)), tostring(d.hostname), strcat("cte-device-", substring(EntityId, 0, 8))),
    DeviceUser = tostring(d.deviceUser),
    DeviceOs = tostring(d.deviceOs),
    DeviceVersion = tostring(d.deviceVersion),
    RuleId = tostring(d.ruleId),
    RuleName = iff(isnotempty(tostring(d.ruleName)), tostring(d.ruleName), "Pattern Match"),
    Pattern = tostring(d.pattern),
    Url = tostring(d.url),
    Action = tostring(d.action),
    IsIoc = tobool(d.ioc),
    ClientIp = tostring(split(tostring(d.clientIp), ":")[0]),
    ClientPort = tostring(split(tostring(d.clientIp), ":")[1]),
    UserAgent = tostring(d.userAgent)
| summarize BlockCount=count(), SampleUrls=make_set(Url, 20), SampleIps=make_set(ClientIp, 20), LastHit=max(TimeGenerated) by bin(TimeGenerated, 10m), HostName, DeviceId, DeviceUser, DeviceOs, TenantId
| where BlockCount >= 15
| extend Url = tostring(SampleUrls[0]), ClientIp = tostring(SampleIps[0])

Declared entities

HostURLIP

Related content

Links established from declared identifiers and solution manifests.

Source provenance

GitHub

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

Source identifier
fbbf3418-f1d8-4bd5-b7da-137a70af6bce
Additional source files 2Solutions/Cybereinforce/Analytic Rules/SuddenBlockSpikeDetected.yamlsource ↗Solutions/Cybereinforce/Data/Solution_Cybereinforce.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.