Detect CVE-2025-62221 Microsoft Windows Use After Free Exploitation in Splunk
Detects exploitation attempts of CVE-2025-62221, a use-after-free vulnerability in Microsoft Windows. This class of memory corruption flaw allows attackers to execute arbitrary code by manipulating freed memory objects. As a CISA KEV entry, active exploitation in the wild has been confirmed. Detection focuses on anomalous process behavior, kernel-mode memory corruption indicators, crash telemetry, and privilege escalation patterns consistent with UAF exploitation chains.
MITRE ATT&CK
- Tactic
- Privilege Escalation Execution
SPL Detection Query
index=windows (sourcetype=WinEventLog:Security OR sourcetype=XmlWinEventLog:Microsoft-Windows-Sysmon/Operational OR sourcetype=crowdstrike:events:sensor)
| eval timeframe=relative_time(now(), "-24h")
| where _time >= timeframe
| eval is_system_proc=if(match(lower(Image), "(lsass|csrss|winlogon|services|svchost)\.exe$"), 1, 0)
| eval is_parent_system=if(match(lower(ParentImage), "(lsass|csrss|winlogon|services|svchost)\.exe$"), 1, 0)
| eval uaf_indicator=case(
(EventCode=4688 AND is_parent_system=1 AND is_system_proc=0), "anomalous_child_from_system_parent",
(EventCode=1 AND IntegrityLevel="High" AND is_parent_system=1 AND is_system_proc=0), "elevated_child_from_system_parent",
match(lower(CommandLine), "(exploit|shellcode|heap.spray|rop.chain)"), "exploit_keyword_in_cmdline",
match(lower(Image), "(exploit|shellcode)"), "suspicious_image_name",
1=1, null()
)
| where isnotnull(uaf_indicator)
| stats count min(_time) as first_seen max(_time) as last_seen values(uaf_indicator) as indicators values(CommandLine) as commands by host, user, Image, ParentImage
| eval cve="CVE-2025-62221"
| sort - countDetects Windows use-after-free exploitation indicators including anomalous process ancestry from system processes, elevated privilege spawning, and exploit keyword patterns in Sysmon and Windows Security event data.
Data Sources
Required Sourcetypes
False Positives & Tuning
- Legitimate administrative tools launching from system process context during patching or maintenance windows
- AV and EDR products performing in-process scanning that may match exploit keyword heuristics
- Developer tools and debuggers that spawn from system parents during legitimate testing
- Automated deployment systems running elevated processes from service parents
Other platforms for CVE-2025-62221
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 1Simulate UAF-style anomalous child process from lsass.exe parent (lab only)
Expected signal: Sysmon Event ID 1 with ParentImage pointing to lsass.exe and Image of cmd.exe; Windows Security EventID 4688 with anomalous parent-child relationship
- Test 2WER crash trigger on system process to simulate pre-exploit crash artifacts
Expected signal: Windows Event ID 1000 (Application Error) and 1001 (Windows Error Reporting) in Application event log; WER report created in %LOCALAPPDATA%\Microsoft\Windows\WER\ReportQueue
- Test 3Elevated token process launch from spoofed system parent context
Expected signal: Sysmon Event ID 1 showing cmd.exe with IntegrityLevel=System spawned by psexec service; Windows Security EventID 4688 with elevated token; EventID 4672 (special privileges assigned to new logon)
- Test 4Heap spray pattern simulation via PowerShell memory allocation
Expected signal: PowerShell Script Block Logging (EventID 4104) capturing the allocation loop; potential AMSI or Defender behavioral alert on large sequential memory allocation patterns
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Get the full detection package for CVE-2025-62221 including response playbook, investigation guide, and atomic red team tests.