High severity malicious activity detected

Status: available
Severity: high
Time window: 1d
Group by: SourceIp, ThreatCategory
Source: github.com/Azure/Azure-Sentinel

Identifies high severity malicious activity in Azure Firewall IDPS logs.

MITRE ATT&CK coverage

Tactic	Techniques
Initial Access	`T1190` Exploit Public-Facing Application
Execution	`T1204` User Execution
Credential Access	`T1003` OS Credential Dumping
Exfiltration	`T1041` Exfiltration Over C2 Channel

Rule body kusto

id: 504257c1-81e2-4609-8d40-b395e62f11c7
name: High severity malicious activity detected
description: |
  Identifies high severity malicious activity in Azure Firewall IDPS logs.
severity: High
status: Available
requiredDataConnectors:
  - connectorId: AzureFirewall
    dataTypes:
      - AZFWIdpsSignature
queryFrequency: 1h
queryPeriod: 24h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - InitialAccess
  - Exfiltration
  - CredentialAccess
  - CommandAndControl
  - Execution
relevantTechniques:
  - T1190
  - T1041
  - T1003
  - T1204
query: |
  let TimeWindow   = 90d;    // How far back to look 
  let HitThreshold = 10;     // Minimum hits to alert per SourceIp + Category
  let MinSeverity  = 1;      // Set Minimum Severity
  let EnableCategoryFilter    = true;   // Filter 1: use CategoriesOfInterest
  let EnableDescriptionFilter = false;  // Filter 2: use DescriptionsOfInterest
  let EnableActionFilter      = false;  // Filter 3: use MatchActions
  let CategoriesOfInterest    = dynamic([
      "Targeted Malicious Activity was Detected",
      "Exploit Kit Activity Detected",
      "Domain Observed Used for C2 Detected",
      "Successful Credential Theft Detected",
      "Malware Command and Control Activity Detected",
      "Executable code was detected",
      "A Network Trojan was detected"
  ]);
  let DescriptionsOfInterest  = dynamic([
      "targeted-activity",
      "exploit-kit",
      "domain-c2",
      "credential-theft",
      "command-and-control",
      "shellcode-detect",
      "trojan-activity"
  ]);
  let MatchActions = dynamic(["Deny", "alert"]);
  AZFWIdpsSignature
  | where TimeGenerated >= ago(TimeWindow)
  | where Severity >= MinSeverity
  // Filter 1: Category filter (optional)
  | where (EnableCategoryFilter == false) or (Category has_any (CategoriesOfInterest))
  // Filter 2: Description filter (optional)
  | where (EnableDescriptionFilter == false) or (Description has_any (DescriptionsOfInterest))
  // Filter 3: Action filter (optional)
  | where (EnableActionFilter == false) or (Action in~ (MatchActions))
  | summarize
      StartTime   = min(TimeGenerated),
      EndTime     = max(TimeGenerated),
      TotalHits   = count(),
      MaxSeverity = max(Severity),
      Actions     = make_set(Action, 5),
      Signatures  = make_set(SignatureId, 20),
      Description = make_set(substring(tostring(Description), 0, 120), 3)
      by SourceIp, ThreatCategory = Category
  | where TotalHits >= HitThreshold
  | project
      StartTime,
      EndTime,
      SourceIp,
      ThreatCategory,
      TotalHits,
      MaxSeverity,
      Actions,
      Signatures,
      Description
  | order by MaxSeverity desc, TotalHits desc
entityMappings:
  - entityType: IP
    fieldMappings:
      - identifier: Address
        columnName: SourceIp
version: 1.0.1
kind: Scheduled

Stages and Predicates

Parameters

let TimeWindow = 90d;
let HitThreshold = 10;
let MinSeverity = 1;
let EnableCategoryFilter = true;
let EnableDescriptionFilter = false;
let EnableActionFilter = false;
let MatchActions = dynamic(["Deny", "alert"]);

Let binding: `CategoriesOfInterest`

let CategoriesOfInterest = dynamic([
    "Targeted Malicious Activity was Detected",
    "Exploit Kit Activity Detected",
    "Domain Observed Used for C2 Detected",
    "Successful Credential Theft Detected",
    "Malware Command and Control Activity Detected",
    "Executable code was detected",
    "A Network Trojan was detected"
]);

Let binding: `DescriptionsOfInterest`

let DescriptionsOfInterest = dynamic([
    "targeted-activity",
    "exploit-kit",
    "domain-c2",
    "credential-theft",
    "command-and-control",
    "shellcode-detect",
    "trojan-activity"
]);

Stage 1: `source`

AZFWIdpsSignature

Stage 2: `where`

| where TimeGenerated >= ago(TimeWindow)

Stage 3: `where`

| where Severity >= MinSeverity

Stage 4: `where`

| where (EnableCategoryFilter == false) or (Category has_any (CategoriesOfInterest))

References CategoriesOfInterest (defined above).

Stage 5: `where`

| where (EnableDescriptionFilter == false) or (Description has_any (DescriptionsOfInterest))

References DescriptionsOfInterest (defined above).

Stage 6: `where`

| where (EnableActionFilter == false) or (Action in~ (MatchActions))

Stage 7: `summarize`

| summarize
    StartTime   = min(TimeGenerated),
    EndTime     = max(TimeGenerated),
    TotalHits   = count(),
    MaxSeverity = max(Severity),
    Actions     = make_set(Action, 5),
    Signatures  = make_set(SignatureId, 20),
    Description = make_set(substring(tostring(Description), 0, 120), 3)
    by SourceIp, ThreatCategory = Category

Threshold: ge 10

Stage 8: `where`

| where TotalHits >= HitThreshold

Stage 9: `project`

| project
    StartTime,
    EndTime,
    SourceIp,
    ThreatCategory,
    TotalHits,
    MaxSeverity,
    Actions,
    Signatures,
    Description

Stage 10: `sort`

| order by MaxSeverity desc, TotalHits desc

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.

Field	Kind	Values
`Action`	in	`Deny` `alert`
`Category`	match	`A Network Trojan was detected` `Domain Observed Used for C2 Detected` `Executable code was detected` `Exploit Kit Activity Detected` `Malware Command and Control Activity Detected` `Successful Credential Theft Detected` `Targeted Malicious Activity was Detected`
`Description`	match	`command-and-control` `credential-theft` `domain-c2` `exploit-kit` `shellcode-detect` `targeted-activity` `trojan-activity`
`Severity`	ge	`1` transforms: `cased`
`TotalHits`	ge	`10` 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.

Field	Source
`Actions`	`project`
`Description`	`project`
`EndTime`	`project`
`MaxSeverity`	`project`
`Signatures`	`project`
`SourceIp`	`project`
`StartTime`	`project`
`ThreatCategory`	`project`
`TotalHits`	`project`

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

High severity malicious activity detected

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Parameters

Let binding: `CategoriesOfInterest`

Let binding: `DescriptionsOfInterest`

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `where`

Stage 5: `where`

Stage 6: `where`

Stage 7: `summarize`

Stage 8: `where`

Stage 9: `project`

Stage 10: `sort`

Indicators

Output fields

Keyboard shortcuts

Search operators

High severity malicious activity detected

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Parameters

Let binding: CategoriesOfInterest

Let binding: DescriptionsOfInterest

Stage 1: source

Stage 2: where

Stage 3: where

Stage 4: where

Stage 5: where

Stage 6: where

Stage 7: summarize

Stage 8: where

Stage 9: project

Stage 10: sort

Indicators

Output fields

Let binding: `CategoriesOfInterest`

Let binding: `DescriptionsOfInterest`

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `where`

Stage 5: `where`

Stage 6: `where`

Stage 7: `summarize`

Stage 8: `where`

Stage 9: `project`

Stage 10: `sort`