Execution of software vulnerable to webp buffer overflow of CVE-2023-4863

Status: available
Severity: informational
Time window: 1h
Source: github.com/Azure/Azure-Sentinel

This query looks at device, process, and network events from Defender for Endpoint that may be vulnerable to buffer overflow defined in CVE-2023-4863. Results are not an indicator of malicious activity.

MITRE ATT&CK coverage

Tactic	Techniques
Execution	`T1203` Exploitation for Client Execution

Event coverage

Provider	Event/ActionType	Title
Sysmon	Event ID 1	Process creation
Security-Auditing	Event ID 4688	A new process has been created.
Security-Auditing	Event ID 5156	The Windows Filtering Platform has permitted a connection.
Defender-DeviceProcessEvents	any	Process activity (any)

Rule body kusto

id: 26e81021-2de6-4442-a74a-a77885e96911
name: Execution of software vulnerable to webp buffer overflow of CVE-2023-4863
description: |
    'This query looks at device, process, and network events from Defender for Endpoint that may be vulnerable to buffer overflow defined in CVE-2023-4863. Results are not an indicator of malicious activity.'
severity: Informational
status: Available
kind: Scheduled
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - Execution
relevantTechniques:
  - T1203
tags:
  - CVE-2023-4863
requiredDataConnectors:
  - connectorId: MicrosoftThreatProtection
    dataTypes:
      - DeviceProcessEvents
      - DeviceNetworkEvents
      - DeviceEvents
      - DeviceTvmSoftwareVulnerabilities
query: |-
  //CVE-2023-4863 Process activity with .webp files on devices where CVE-2023-4863 is unpatched
  //This query shows all process activity with .webp files on vulnerable machines and is not an indicator of malicious activity
  let VulnDevices = DeviceTvmSoftwareVulnerabilities
      | where CveId == "CVE-2023-4863"
      | distinct DeviceId;
  union DeviceProcessEvents, DeviceNetworkEvents, DeviceEvents
  | where DeviceId in (VulnDevices) and (InitiatingProcessCommandLine has(".webp") or ProcessCommandLine has(".webp"))
  | extend Name = tostring(split(AccountUpn, "@")[0]), UPNSuffix = tostring(split(AccountUpn, "@")[1])
  | extend HostName = tostring(split(DeviceName, ".")[0]), DomainIndex = toint(indexof(DeviceName, '.'))
  | extend HostNameDomain = iff(DomainIndex != -1, substring(DeviceName, DomainIndex + 1), DeviceName)
entityMappings:
- entityType: Host
  fieldMappings:
    - identifier: FullName
      columnName: DeviceName
    - identifier: HostName
      columnName: HostName
    - identifier: DnsDomain
      columnName: HostNameDomain
- entityType: Account
  fieldMappings:
    - identifier: FullName
      columnName: AccountUpn
    - identifier: Name
      columnName: Name
    - identifier: UPNSuffix
      columnName: UPNSuffix
- entityType: IP
  fieldMappings:
    - identifier: Address
      columnName: LocalIP
- entityType: Process
  fieldMappings:
    - identifier: ProcessId
      columnName: ProcessId
- entityType: Process
  fieldMappings:
    - identifier: ProcessId
      columnName: InitiatingProcessId
- entityType: Process
  fieldMappings:
    - identifier: CommandLine
      columnName: ProcessCommandLine
suppressionEnabled: false
incidentConfiguration:
  createIncident: false
  groupingConfiguration:
    enabled: false
    reopenClosedIncident: false
    lookbackDuration: PT5H
    matchingMethod: Selected
    groupByEntities:
    - Account
    groupByAlertDetails: []
    groupByCustomDetails: []
suppressionDuration: PT5H
alertDetailsOverride:
  alertDisplayNameFormat: Possible exploitation of CVE-2023-4863
  alertDynamicProperties: []
eventGroupingSettings:
  aggregationKind: SingleAlert
version: 1.1.2

Stages and Predicates

Let binding: `VulnDevices`

let VulnDevices = DeviceTvmSoftwareVulnerabilities
    | where CveId == "CVE-2023-4863"
    | distinct DeviceId;

union (3 sources)

Each leg below queries one source; the rule matches if any leg does. Sources: DeviceProcessEvents, DeviceNetworkEvents, DeviceEvents

Leg 1: `DeviceProcessEvents`

Leg 2: `DeviceNetworkEvents`

Leg 3: `DeviceEvents`

Applied to the combined result

| where DeviceId in (VulnDevices) and (InitiatingProcessCommandLine has(".webp") or ProcessCommandLine has(".webp")) | extend Name = tostring(split(AccountUpn, "@")[0]), UPNSuffix = tostring(split(AccountUpn, "@")[1]) | extend HostName = tostring(split(DeviceName, ".")[0]), DomainIndex = toint(indexof(DeviceName, '.')) | extend HostNameDomain = iff(DomainIndex != -1, substring(DeviceName, DomainIndex + 1), DeviceName)

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
`DeviceId`	in	`VulnDevices` transforms: `cased`
`InitiatingProcessCommandLine`	match	`.webp` transforms: `term`
`ProcessCommandLine`	match	`.webp` transforms: `term` corpus 2 (sigma 1, kusto 1)

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
`Name`	`extend`
`UPNSuffix`	`extend`
`DomainIndex`	`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)

Execution of software vulnerable to webp buffer overflow of CVE-2023-4863

MITRE ATT&CK coverage

Event coverage

Rule body kusto

Stages and Predicates

Let binding: `VulnDevices`

union (3 sources)

Leg 1: `DeviceProcessEvents`

Leg 2: `DeviceNetworkEvents`

Leg 3: `DeviceEvents`

Applied to the combined result

Indicators

Output fields

Keyboard shortcuts

Search operators

Execution of software vulnerable to webp buffer overflow of CVE-2023-4863

MITRE ATT&CK coverage

Event coverage

Rule body kusto

Stages and Predicates

Let binding: VulnDevices

union (3 sources)

Leg 1: DeviceProcessEvents

Leg 2: DeviceNetworkEvents

Leg 3: DeviceEvents

Applied to the combined result

Indicators

Output fields

Let binding: `VulnDevices`

Leg 1: `DeviceProcessEvents`

Leg 2: `DeviceNetworkEvents`

Leg 3: `DeviceEvents`