SUNBURST suspicious SolarWinds child processes (Normalized Process Events)

Severity: medium
Time window: 1d
Author: Yuval Naor
Source: github.com/Azure/Azure-Sentinel

Identifies suspicious child processes of SolarWinds.Orion.Core.BusinessLayer.dll that may be evidence of the SUNBURST backdoor References: - https://www.fireeye.com/blog/threat-research/2020/12/evasive-attacker-leverages-solarwinds-supply-chain-compromises-with-sunburst-backdoor.html - https://gist.github.com/olafhartong/71ffdd4cab4b6acd5cbcd1a0691ff82f To use this analytics rule, make sure you have deployed the ASIM normalization parsers'

MITRE ATT&CK coverage

Tactic	Techniques
Execution	`T1059` Command and Scripting Interpreter
Persistence	`T1543` Create or Modify System Process

Event coverage

Provider	Event	Title
Sysmon	Event ID 1	Process creation
Sysmon	Event ID 5	Process terminated
Security-Auditing	Event ID 4688	A new process has been created.
Security-Auditing	Event ID 4689	A process has exited.

Rule body kusto

id: 631d02df-ab51-46c1-8d72-32d0cfec0720
name: SUNBURST suspicious SolarWinds child processes (Normalized Process Events)
description: |
  Identifies suspicious child processes of SolarWinds.Orion.Core.BusinessLayer.dll that may be evidence of the SUNBURST backdoor
  References:
  - https://www.fireeye.com/blog/threat-research/2020/12/evasive-attacker-leverages-solarwinds-supply-chain-compromises-with-sunburst-backdoor.html
  - https://gist.github.com/olafhartong/71ffdd4cab4b6acd5cbcd1a0691ff82f
  To use this analytics rule, make sure you have deployed the [ASIM normalization parsers](https://aka.ms/ASimProcessEvent)'
severity: Medium
requiredDataConnectors: []
queryFrequency: 1d
queryPeriod: 1d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Execution
  - Persistence
relevantTechniques:
  - T1059
  - T1543
tags:
  - Id: 4a3073ac-7383-48a9-90a8-eb6716183a54
    version: 1.0.0
  - Schema: ASIMProcessEvent
    SchemaVersion: 0.1.0
  - Solorigate
  - NOBELIUM

query:  |
  let excludeProcs = dynamic([@"\SolarWinds\Orion\APM\APMServiceControl.exe", @"\SolarWinds\Orion\ExportToPDFCmd.Exe", @"\SolarWinds.Credentials\SolarWinds.Credentials.Orion.WebApi.exe", @"\SolarWinds\Orion\Topology\SolarWinds.Orion.Topology.Calculator.exe", @"\SolarWinds\Orion\Database-Maint.exe", @"\SolarWinds.Orion.ApiPoller.Service\SolarWinds.Orion.ApiPoller.Service.exe", @"\Windows\SysWOW64\WerFault.exe"]);
  imProcessCreate
  | where Process hassuffix 'solarwinds.businesslayerhost.exe'
  | where not(Process has_any (excludeProcs))
  | extend AccountName = tostring(split(ActorUsername, @'\')[1]), AccountNTDomain = tostring(split(ActorUsername, @'\')[0])
  | extend HostName = tostring(split(Dvc, ".")[0]), DomainIndex = toint(indexof(Dvc, '.'))
  | extend HostNameDomain = iff(DomainIndex != -1, substring(Dvc, DomainIndex + 1), Dvc)
  | project-away DomainIndex
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: FullName
        columnName: ActorUsername
      - identifier: Name
        columnName: AccountName
      - identifier: NTDomain
        columnName: AccountNTDomain
  - entityType: Host
    fieldMappings:
      - identifier: FullName
        columnName: Dvc
      - identifier: HostName
        columnName: HostName
      - identifier: DnsDomain
        columnName: HostNameDomain
  - entityType: FileHash
    fieldMappings:
      - identifier: Algorithm
        columnName: AlgorithmType
      - identifier: Value
        columnName: TargetFileMD5
version: 1.1.6
kind: Scheduled
metadata:
    source:
        kind: Community
    author:
        name: Yuval Naor
    support:
        tier: Community
    categories:
        domains: [ "Security - 0-day Vulnerability" ]

Stages and Predicates

Let binding: `excludeProcs`

let excludeProcs = dynamic([@"\SolarWinds\Orion\APM\APMServiceControl.exe", @"\SolarWinds\Orion\ExportToPDFCmd.Exe", @"\SolarWinds.Credentials\SolarWinds.Credentials.Orion.WebApi.exe", @"\SolarWinds\Orion\Topology\SolarWinds.Orion.Topology.Calculator.exe", @"\SolarWinds\Orion\Database-Maint.exe", @"\SolarWinds.Orion.ApiPoller.Service\SolarWinds.Orion.ApiPoller.Service.exe", @"\Windows\SysWOW64\WerFault.exe"]);

Stage 1: `source`

imProcessCreate

Stage 2: `where`

| where Process hassuffix 'solarwinds.businesslayerhost.exe'

Stage 3: `where`

| where not(Process has_any (excludeProcs))

References excludeProcs (defined above).

Stage 4: `extend` (3 consecutive steps)

| extend AccountName = tostring(split(ActorUsername, @'\')[1]), AccountNTDomain = tostring(split(ActorUsername, @'\')[0])
| extend HostName = tostring(split(Dvc, ".")[0]), DomainIndex = toint(indexof(Dvc, '.'))
| extend HostNameDomain = iff(DomainIndex != -1, substring(Dvc, DomainIndex + 1), Dvc)

Stage 5: `project-away`

| project-away DomainIndex

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

Field	Kind	Excluded values
`Process`	match	`\SolarWinds\Orion\APM\APMServiceControl.exe`, `\SolarWinds\Orion\ExportToPDFCmd.Exe`, `\SolarWinds.Credentials\SolarWinds.Credentials.Orion.WebApi.exe`, `\SolarWinds\Orion\Topology\SolarWinds.Orion.Topology.Calculator.exe`, `\SolarWinds\Orion\Database-Maint.exe`, `\SolarWinds.Orion.ApiPoller.Service\SolarWinds.Orion.ApiPoller.Service.exe`, `\Windows\SysWOW64\WerFault.exe`

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
`Process`	ends_with	`solarwinds.businesslayerhost.exe`

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
`AccountNTDomain`	`extend`
`AccountName`	`extend`
`HostName`	`extend`
`HostNameDomain`	`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)

SUNBURST suspicious SolarWinds child processes (Normalized Process Events)

MITRE ATT&CK coverage

Event coverage

Rule body kusto

Stages and Predicates

Let binding: `excludeProcs`

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `extend` (3 consecutive steps)

Stage 5: `project-away`

Exclusions

Indicators

Output fields

Keyboard shortcuts

Search operators

SUNBURST suspicious SolarWinds child processes (Normalized Process Events)

MITRE ATT&CK coverage

Event coverage

Rule body kusto

Stages and Predicates

Let binding: excludeProcs

Stage 1: source

Stage 2: where

Stage 3: where

Stage 4: extend (3 consecutive steps)

Stage 5: project-away

Exclusions

Indicators

Output fields

Let binding: `excludeProcs`

Stage 1: `source`

Stage 2: `where`

Stage 3: `where`

Stage 4: `extend` (3 consecutive steps)

Stage 5: `project-away`