Pure Controller Failed

Severity: high
Source: github.com/Azure/Azure-Sentinel

Detect controller failure and take appropriate response action.

MITRE ATT&CK coverage

Tactic	Techniques
Execution	`T0871` Execution through API

Rule body kusto

id: c317b007-84e7-4449-93f4-4444f6638fd0
name: Pure Controller Failed
version: 1.0.0
kind: NRT
description: Detect controller failure and take appropriate response action.
severity: High
tactics:
- Execution
relevantTechniques:
- T0871
query: |-
  Syslog
  | where SyslogMessage has "purity.alert"
  | extend Message = replace_regex(SyslogMessage, "#012", "\n")
  | extend ParsedLog = extract_all(@"((?P<process>.*?)\[(?P<processid>.*?)\]:\s(?P<object>.*)\[(?P<responsecode>\w+)\][\s\S]*Severity:\s*(?P<severity>\S+)\s*(Tag:\s*(?P<reason>\S+))?\s*UTC([\s\S]*)Array Name:\s*(?P<objectname>\S+)\s*Domain:\s*(?P<domainorigin>\S+)\s*(?P<part2log>[\s\S]*))", dynamic(['process','processid','object','objectname','responsecode','severity','reason','domainorigin','part2log']), Message)
  | mv-expand ParsedLog
  | extend ResidueLog = tostring(ParsedLog[8])
  | extend Rlog = extract_all(@"(((Suggested Action:\s*(?P<action>[\s\S]*)\s*Knowledge Base Article:\s*(?P<url>.*))|(Knowledge Base Article:\s*(?P<url>.*)\s*Suggested Action:\s*(?P<action>.*)\s*)|(Suggested Action:\s*(?P<action>[\s\S]*)))(([\s\S]*)Purity Version:\s*(?P<pversion>.*))?\s*([\s\S]*)Variables: \(below\)\s*(?P<subject>[\s\S]*))", dynamic(['action','url','pversion','subject']),ResidueLog)
  | mv-expand Rlog
  | extend PureLogType = ParsedLog[0], PureProcessID = ParsedLog[1], PureObject = ParsedLog[2], PureCode = ParsedLog[4], PureSeverity = ParsedLog[5], PureReason = ParsedLog[6], PureObjectName = ParsedLog[3], PureDomainOrigin = ParsedLog[7], PureAction = Rlog[0], PureUrl = Rlog[1], PureVersion = Rlog[2], PureMessage = Rlog[3]
  | project-away ResidueLog, Rlog, ParsedLog
  | where PureObject matches regex @"(Controllers ct[0-9] have failed)"
suppressionDuration: 5h
suppressionEnabled: false
eventGroupingSettings:
  aggregationKind: SingleAlert
alertDetailsOverride:
  alertDynamicProperties: []
entityMappings:
- entityType: IP
  fieldMappings:
  - identifier: Address
    columnName: HostIP
incidentConfiguration:
  createIncident: true
  groupingConfiguration:
    enabled: false
    reopenClosedIncident: false
    lookbackDuration: PT5H
    matchingMethod: AllEntities
    groupByEntities: []
    groupByAlertDetails: []
    groupByCustomDetails: []

Stages and Predicates

Stage 1: `source`

Syslog

Stage 2: `where`

| where SyslogMessage has "purity.alert"

Stage 3: `extend`

| extend Message = replace_regex(SyslogMessage, "#012", "\n")

Stage 4: `extend`

| extend ParsedLog = extract_all(@"((?P<process>.*?)\[(?P<processid>.*?)\]:\s(?P<object>.*)\[(?P<responsecode>\w+)\][\s\S]*Severity:\s*(?P<severity>\S+)\s*(Tag:\s*(?P<reason>\S+))?\s*UTC([\s\S]*)Array Name:\s*(?P<objectname>\S+)\s*Domain:\s*(?P<domainorigin>\S+)\s*(?P<part2log>[\s\S]*))", dynamic(['process','processid','object','objectname','responsecode','severity','reason','domainorigin','part2log']), Message)

Stage 5: `mv-expand`

| mv-expand ParsedLog

Stage 6: `extend`

| extend ResidueLog = tostring(ParsedLog[8])

Stage 7: `extend`

| extend Rlog = extract_all(@"(((Suggested Action:\s*(?P<action>[\s\S]*)\s*Knowledge Base Article:\s*(?P<url>.*))|(Knowledge Base Article:\s*(?P<url>.*)\s*Suggested Action:\s*(?P<action>.*)\s*)|(Suggested Action:\s*(?P<action>[\s\S]*)))(([\s\S]*)Purity Version:\s*(?P<pversion>.*))?\s*([\s\S]*)Variables: \(below\)\s*(?P<subject>[\s\S]*))", dynamic(['action','url','pversion','subject']),ResidueLog)

Stage 8: `mv-expand`

| mv-expand Rlog

Stage 9: `extend`

| extend PureLogType = ParsedLog[0], PureProcessID = ParsedLog[1], PureObject = ParsedLog[2], PureCode = ParsedLog[4], PureSeverity = ParsedLog[5], PureReason = ParsedLog[6], PureObjectName = ParsedLog[3], PureDomainOrigin = ParsedLog[7], PureAction = Rlog[0], PureUrl = Rlog[1], PureVersion = Rlog[2], PureMessage = Rlog[3]

Stage 10: `project-away`

| project-away ResidueLog, Rlog, ParsedLog

Stage 11: `where`

| where PureObject matches regex @"(Controllers ct[0-9] have failed)"

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
`PureObject`	regex_match	`(Controllers ct[0-9] have failed)`
`SyslogMessage`	match	`purity.alert` transforms: `term`

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
`Message`	`extend`
`PureAction`	`extend`
`PureCode`	`extend`
`PureDomainOrigin`	`extend`
`PureLogType`	`extend`
`PureMessage`	`extend`
`PureObject`	`extend`
`PureObjectName`	`extend`
`PureProcessID`	`extend`
`PureReason`	`extend`
`PureSeverity`	`extend`
`PureUrl`	`extend`
`PureVersion`	`extend`

`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)

Pure Controller Failed

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Stage 1: `source`

Stage 2: `where`

Stage 3: `extend`

Stage 4: `extend`

Stage 5: `mv-expand`

Stage 6: `extend`

Stage 7: `extend`

Stage 8: `mv-expand`

Stage 9: `extend`

Stage 10: `project-away`

Stage 11: `where`

Indicators

Output fields

Keyboard shortcuts

Search operators

Pure Controller Failed

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Stage 1: source

Stage 2: where

Stage 3: extend

Stage 4: extend

Stage 5: mv-expand

Stage 6: extend

Stage 7: extend

Stage 8: mv-expand

Stage 9: extend

Stage 10: project-away

Stage 11: where

Indicators

Output fields

Stage 1: `source`

Stage 2: `where`

Stage 3: `extend`

Stage 4: `extend`

Stage 5: `mv-expand`

Stage 6: `extend`

Stage 7: `extend`

Stage 8: `mv-expand`

Stage 9: `extend`

Stage 10: `project-away`

Stage 11: `where`