Detect Microsoft Office Word Reliance on Untrusted Inputs in Security Decision (CVE-2026-21514) in IBM QRadar
Detects exploitation of CVE-2026-21514, a Microsoft Office Word vulnerability classified as CWE-807 (Reliance on Untrusted Inputs in a Security Decision). This flaw allows attackers to manipulate security-relevant decisions in Word by supplying crafted untrusted input, potentially bypassing security controls such as Protected View, macro policy enforcement, or document trust decisions. This CVE is listed on the CISA KEV catalog, indicating active exploitation in the wild.
MITRE ATT&CK
QRadar Detection Query
SELECT DATEFORMAT(starttime,'YYYY-MM-dd HH:mm:ss') AS event_time,
sourceip, username, "Process Name", "Parent Process Name", "Command"
FROM events
WHERE LOGSOURCETYPENAME(devicetype) IN ('Microsoft Windows Security Event Log', 'Sysmon')
AND ("Parent Process Name" ILIKE '%WINWORD.EXE'
AND "Process Name" ILIKE ANY ('%cmd.exe','%powershell.exe','%wscript.exe',
'%cscript.exe','%mshta.exe','%rundll32.exe',
'%regsvr32.exe','%certutil.exe','%bitsadmin.exe',
'%msiexec.exe'))
LAST 7 DAYS
ORDER BY starttime DESCQRadar AQL query detecting WINWORD.EXE as a parent process for known LOLBins and scripting engines, sourced from Windows Security or Sysmon log sources.
Data Sources
Required Tables
False Positives & Tuning
- Enterprise Word automation solutions that use cmd or PowerShell as part of approved workflows
- Managed endpoint software that hooks Word and spawns system utilities during updates
- Security tools running in audit or simulation mode against Word processes
- Custom Word add-ins developed internally that use scripting engines for business logic
Other platforms for CVE-2026-21514
Testing Methodology
Validate this detection against 4 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Word Spawns PowerShell via Macro — Security Bypass Simulation
Expected signal: Sysmon Event ID 1 showing WINWORD.EXE as ParentImage with powershell.exe as child Image; PowerShell ScriptBlock logging Event ID 4104; network telemetry if payload attempts outbound connection
- Test 2Word Drops Executable to Temp via Macro
Expected signal: Sysmon Event ID 11 (FileCreate) with Image=WINWORD.EXE and TargetFilename ending in .exe under %TEMP%; DeviceFileEvents in MDE showing InitiatingProcessFileName=WINWORD.EXE
- Test 3Word Initiates External Network Connection via mshta Child Process
Expected signal: Sysmon Event ID 1 with ParentImage=WINWORD.EXE and Image=mshta.exe; subsequent cmd.exe spawn from mshta.exe visible in process tree; file creation in TEMP
- Test 4Mark-of-the-Web Bypass Check — Simulated Internet-Origin Document Open
Expected signal: Sysmon Event ID 15 (FileCreateStreamHash) capturing Zone.Identifier ADS creation and deletion; Windows Defender SmartScreen or Office MOTW telemetry in event logs
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