Detect Microsoft Windows Information Disclosure (CVE-2026-20805) in Microsoft Sentinel
Detects exploitation of CVE-2026-20805, a Microsoft Windows information disclosure vulnerability (CWE-200) that allows attackers to access sensitive memory or kernel data. This vulnerability is actively exploited in the wild (CISA KEV). Successful exploitation may expose credentials, memory contents, or system information that enables privilege escalation or lateral movement.
MITRE ATT&CK
KQL Detection Query
let timeWindow = 24h;
union DeviceEvents, DeviceProcessEvents
| where Timestamp > ago(timeWindow)
| where DeviceId in (
DeviceInfo
| where OSPlatform startswith "Windows"
| distinct DeviceId
)
| where (ActionType in ("SensitiveFileRead", "CredentialAccess", "KernelDriverLoaded", "NtQuerySystemInformation") or
(ProcessCommandLine has_any ("NtQuerySystemInformation", "ZwQuerySystemInformation", "ReadProcessMemory", "OpenProcess") and
InitiatingProcessIntegrityLevel in~ ("Low", "Medium")))
| extend SuspiciousScore = case(
InitiatingProcessIntegrityLevel =~ "Low" and ActionType == "KernelDriverLoaded", 3,
ProcessCommandLine has_any ("NtQuerySystemInformation", "ZwQuerySystemInformation"), 2,
ActionType == "SensitiveFileRead" and InitiatingProcessAccountName !in~ ("SYSTEM", "LOCAL SERVICE", "NETWORK SERVICE"), 2,
1)
| where SuspiciousScore >= 2
| summarize EventCount = count(), Actions = make_set(ActionType), Processes = make_set(InitiatingProcessFileName), Score = max(SuspiciousScore) by DeviceId, DeviceName, InitiatingProcessAccountName, bin(Timestamp, 1h)
| where EventCount >= 2
| project Timestamp, DeviceName, DeviceId, AccountName = InitiatingProcessAccountName, Actions, Processes, EventCount, Score
| order by Score desc, EventCount descDetects patterns consistent with CVE-2026-20805 exploitation: low/medium integrity processes invoking Windows kernel information disclosure APIs (NtQuerySystemInformation, ZwQuerySystemInformation) or performing sensitive file reads outside of expected SYSTEM-level context.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate security scanning tools (e.g., Sysinternals ProcMon, Process Hacker) querying system information
- Antivirus or EDR agents performing routine kernel-level enumeration
- System administration scripts running under non-SYSTEM accounts with elevated permissions
- Performance monitoring software reading process or memory metrics
Other platforms for CVE-2026-20805
Testing Methodology
Validate this detection against 3 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 1NtQuerySystemInformation via PowerShell P/Invoke
Expected signal: Sysmon Event ID 1 (Process Create) for powershell.exe; Windows Event ID 4688 if process command line auditing is enabled; EDR process telemetry capturing the PowerShell invocation with P/Invoke patterns.
- Test 2LSASS Handle Open with VM_READ Access
Expected signal: Sysmon Event ID 10 (ProcessAccess) with TargetImage=lsass.exe, GrantedAccess=0x0010 (PROCESS_VM_READ), SourceImage=powershell.exe; Windows Security Event ID 4656 for handle request to LSASS process object.
- Test 3Sensitive Registry Hive Access from Low Integrity Context
Expected signal: Windows Security Event ID 4663 with ObjectName containing SECURITY hive path; Sysmon Event ID 1 for process creation with low integrity level token; Event ID 4656 for registry key open with sensitive access mask.
Unlock Pro Content
Get the full detection package for CVE-2026-20805 including response playbook, investigation guide, and atomic red team tests.