Detect CVE-2023-36424 - Microsoft Windows Out-of-Bounds Read Exploitation in Google Chronicle
Detects exploitation attempts of CVE-2023-36424, a Microsoft Windows out-of-bounds read vulnerability (CWE-125) listed in CISA's Known Exploited Vulnerabilities catalog. Out-of-bounds read vulnerabilities in Windows kernel or system components can be leveraged for privilege escalation, information disclosure, or as a stepping stone in exploit chains. This detection monitors for anomalous process behavior, crash artifacts, and privilege escalation patterns consistent with exploitation of this class of vulnerability.
MITRE ATT&CK
YARA-L Detection Query
rule cve_2023_36424_windows_oob_read {
meta:
author = "df00tech"
description = "Detects CVE-2023-36424 exploitation indicators: Windows OOB read vulnerability"
severity = "HIGH"
priority = "HIGH"
cve = "CVE-2023-36424"
reference = "https://msrc.microsoft.com/update-guide/en-US/advisory/CVE-2023-36424"
events:
(
$e.metadata.event_type = "PROCESS_LAUNCH"
AND (
re.regex($e.target.process.file.full_path, `(?i)werfault\.exe$`)
OR re.regex($e.target.process.file.full_path, `(?i)reportfault\.exe$`)
)
AND NOT re.regex($e.principal.user.userid, `(?i).*\$$`)
)
OR
(
$e.metadata.event_type = "USER_UNCATEGORIZED"
AND $e.metadata.product_event_type = "4672"
AND NOT re.regex($e.principal.user.userid, `(?i).*\$$`)
AND NOT $e.principal.user.userid = "SYSTEM"
)
condition:
$e
}Chronicle YARA-L rule detecting CVE-2023-36424 exploitation indicators including WerFault.exe process launches from non-system accounts and anomalous special privilege assignment events on Windows endpoints.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate werfault.exe process launches following unrelated software crashes
- Normal privileged user logon events (EventID 4672) on administrative workstations
- Security tools running as non-system users that legitimately trigger error reporting
- Developers testing application stability who trigger WerFault as part of debugging
Other platforms for CVE-2023-36424
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 Out-of-Bounds Read Crash via Malformed Input
Expected signal: Windows Event ID 1000 (Application Error) and 1001 (WER) in Application log; WerFault.exe process launch visible in Sysmon Event ID 1; crash dump file created in %LOCALAPPDATA%\CrashDumps
- Test 2Privilege Escalation Simulation Following Crash Artifact
Expected signal: Windows Event ID 4672 (Special Privileges Assigned) in Security log; Process creation events in Sysmon for cmd.exe and powershell.exe; elevated process token in DeviceProcessEvents
- Test 3Memory Dump Creation Mimicking Exploit Artifact
Expected signal: Sysmon Event ID 11 (FileCreate) for .dmp file in CrashDumps directory; DeviceFileEvents entry for the dump file creation; rundll32.exe process creation with comsvcs.dll MiniDump arguments in process telemetry
- Test 4WerFault.exe Manual Invocation Simulation
Expected signal: Sysmon Event ID 1 showing WerFault.exe launched by PowerShell (non-standard parent); DeviceProcessEvents with FileName=werfault.exe and InitiatingProcessFileName=powershell.exe; potential Event ID 1001 in Application log
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