OMI Vulnerability Exploitation

Severity: medium
Time window: 1d
Group by: Computer
Author: Ron Marsiano
Source: github.com/Azure/Azure-Sentinel

Following the September 14th, 2021 release of three Elevation of Privilege (EoP) vulnerabilities (CVE-2021-38645, CVE-2021-38649, CVE-2021-38648) and one unauthenticated Remote Code Execution (RCE) vulnerability (CVE-2021-38647) in the Open Management Infrastructure (OMI) Framework. This detection validates that any OMS-agent that is reporting to the Microsoft Sentinel workspace is updated with the patch. The detection will go over the heartbeats received from all agents over the last day and will create alert for those agents who are not updated.

MITRE ATT&CK coverage

Tactic	Techniques
Initial Access	`T1190` Exploit Public-Facing Application

Rule body kusto

id: 3cc5ccd8-b416-4141-bb2d-4eba370e37a5
name: OMI Vulnerability Exploitation
description: |
  Following the September 14th, 2021 release of three Elevation of Privilege (EoP) vulnerabilities (CVE-2021-38645, CVE-2021-38649, CVE-2021-38648) and one unauthenticated Remote Code Execution (RCE) vulnerability (CVE-2021-38647) in the Open Management Infrastructure (OMI) Framework.
  This detection validates that any OMS-agent that is reporting to the Microsoft Sentinel workspace is updated with the patch. The detection will go over the heartbeats received from all agents over the last day and will create alert for those agents who are not updated.
requiredDataConnectors: []
severity: Medium
queryFrequency: 1d
queryPeriod: 1d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - InitialAccess
relevantTechniques:
  - T1190
tags:
  - OMIGOD
  - CVE-2021-38647
query: |
  let OMIVulnerabilityPatchVersion = "OMIVulnerabilityPatchVersion:1.13.40-0";
  Heartbeat
  | where Category == "Direct Agent"
  | summarize arg_max(TimeGenerated,*) by Computer
  | parse strcat("Version:" , Version) with * "Version:" Major:long "."
  Minor:long "." Patch:long "-" *
  | parse OMIVulnerabilityPatchVersion with * "OMIVulnerabilityPatchVersion:"
  OMIVersionMajor:long "." OMIVersionMinor:long "." OMIVersionPatch:long "-" *
  | where Major <OMIVersionMajor or (Major==OMIVersionMajor and Minor
  <OMIVersionMinor) or (Major==OMIVersionMajor and Minor==OMIVersionMinor and
  Patch<OMIVersionPatch) 
  | project Version, Major,Minor,Patch,
  Computer,ComputerIP,OSType,OSName,ResourceId
entityMappings:
  - entityType: Host
    fieldMappings:
      - identifier: HostName
        columnName: Computer
  - entityType: AzureResource
    fieldMappings:
      - identifier: ResourceId
        columnName: ResourceId
customDetails:
  HostIp: ComputerIP
  OSType: OSType
  OSName: OSName
kind: Scheduled
version: 1.1.5
metadata:
    source:
        kind: Community
    author:
        name: Ron Marsiano
    support:
        tier: Community
    categories:
        domains: [ "Security - Vulnerability Management" ]

Stages and Predicates

Parameters

let OMIVulnerabilityPatchVersion = "OMIVulnerabilityPatchVersion:1.13.40-0";

Stage 1: `source`

Heartbeat

Stage 2: `where`

| where Category == "Direct Agent"

Stage 3: `summarize`

| summarize arg_max(TimeGenerated,*) by Computer

Stage 4: `parse`

| parse strcat("Version:" , Version) with * "Version:" Major:long "."
Minor:long "." Patch:long "-" *

Stage 5: `parse`

| parse OMIVulnerabilityPatchVersion with * "OMIVulnerabilityPatchVersion:"
OMIVersionMajor:long "." OMIVersionMinor:long "." OMIVersionPatch:long "-" *

Stage 6: `where`

| where Major <OMIVersionMajor or (Major==OMIVersionMajor and Minor
<OMIVersionMinor) or (Major==OMIVersionMajor and Minor==OMIVersionMinor and
Patch<OMIVersionPatch)

Stage 7: `project`

| project Version, Major,Minor,Patch,
Computer,ComputerIP,OSType,OSName,ResourceId

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
`Category`	eq	`Direct Agent` transforms: `cased`
`Major`	eq	`OMIVersionMajor` transforms: `cased`
`Major`	lt	`OMIVersionMajor` transforms: `cased`
`Minor`	eq	`OMIVersionMinor` transforms: `cased`
`Minor`	lt	`OMIVersionMinor` transforms: `cased`
`Patch`	lt	`OMIVersionPatch` 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
`Computer`	`project`
`ComputerIP`	`project`
`Major`	`project`
`Minor`	`project`
`OSName`	`project`
`OSType`	`project`
`Patch`	`project`
`ResourceId`	`project`
`Version`	`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)

OMI Vulnerability Exploitation

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Parameters

Stage 1: `source`

Stage 2: `where`

Stage 3: `summarize`

Stage 4: `parse`

Stage 5: `parse`

Stage 6: `where`

Stage 7: `project`

Indicators

Output fields

Keyboard shortcuts

Search operators

OMI Vulnerability Exploitation

MITRE ATT&CK coverage

Rule body kusto

Stages and Predicates

Parameters

Stage 1: source

Stage 2: where

Stage 3: summarize

Stage 4: parse

Stage 5: parse

Stage 6: where

Stage 7: project

Indicators

Output fields

Stage 1: `source`

Stage 2: `where`

Stage 3: `summarize`

Stage 4: `parse`

Stage 5: `parse`

Stage 6: `where`

Stage 7: `project`