Detect Apple WebKit Use-After-Free Exploitation Attempt (CVE-2025-43529) in Microsoft Sentinel
Detects exploitation attempts targeting CVE-2025-43529, a use-after-free vulnerability in Apple's WebKit browser engine affecting multiple Apple products. This vulnerability is actively exploited in the wild (CISA KEV) and can lead to arbitrary code execution when a user visits a maliciously crafted webpage. Attackers may leverage this flaw to achieve initial access or privilege escalation on macOS, iOS, and iPadOS devices.
MITRE ATT&CK
KQL Detection Query
union DeviceProcessEvents, DeviceNetworkEvents
| where Timestamp > ago(7d)
| where InitiatingProcessFileName in~ ("Safari", "WebKit", "com.apple.WebKit", "WebProcess", "com.apple.WebKit.WebContent")
| where ActionType in ("ProcessCreated", "NetworkConnectionEvents") or FileName in~ ("WebProcess", "com.apple.WebKit.Networking")
| extend SuspiciousChild = iff(
InitiatingProcessFileName in~ ("Safari", "WebProcess") and
FileName in~ ("sh", "bash", "zsh", "python3", "curl", "osascript", "launchctl"),
true, false)
| where SuspiciousChild == true
| project Timestamp, DeviceId, DeviceName, InitiatingProcessFileName, InitiatingProcessCommandLine, FileName, ProcessCommandLine, RemoteIP, RemoteUrl
| summarize count(), make_set(ProcessCommandLine), make_set(RemoteIP) by DeviceId, DeviceName, InitiatingProcessFileName, bin(Timestamp, 1h)Detects WebKit/Safari spawning suspicious child processes that are indicative of post-exploitation activity following a use-after-free vulnerability trigger. Looks for browser processes launching shells, scripting interpreters, or network utilities.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate browser extensions invoking shell helpers in sandboxed environments
- Developer tools or test harnesses running automated browser tests
- macOS software update processes triggered through browser UI
- Security scanning tools that spawn child processes from browser contexts
Other platforms for CVE-2025-43529
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 1Simulate WebKit Child Process Spawn (macOS)
Expected signal: Process creation event: parent=osascript, child=bash; bash executing id and whoami commands
- Test 2WebProcess Curl Outbound Simulation
Expected signal: Network connection event: process=curl, initiated from simulated WebKit parent context, destination=127.0.0.1:9999
- Test 3Launchctl Persistence Attempt Post-WebKit Exploitation
Expected signal: Process creation: launchctl load with plist argument; file write to /tmp/webkit_test/test.plist; LaunchAgent registration event in macOS Unified Log
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