Detect Apple WebKit Use-After-Free Exploitation Attempt (CVE-2025-43529) in Splunk
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
SPL Detection Query
index=* sourcetype IN ("macos:unified_log", "jamf:pro", "crowdstrike:events", "carbon_black:process")
(process_name="WebProcess" OR process_name="com.apple.WebKit.WebContent" OR parent_process_name="Safari" OR parent_process_name="WebProcess")
| eval suspicious_child=if(match(process_name, "(sh|bash|zsh|python3|curl|wget|osascript|launchctl|xterm)"), 1, 0)
| where suspicious_child=1
| stats count min(_time) as firstSeen max(_time) as lastSeen values(process_name) as child_processes values(cmdline) as commands values(dest_ip) as dest_ips by src_host parent_process_name
| eval risk_score=if(count>3, "high", "medium")
| sort -countSplunk detection for WebKit use-after-free exploitation by identifying Safari/WebProcess spawning unexpected shell or scripting interpreter child processes on macOS endpoints.
Data Sources
Required Sourcetypes
False Positives & Tuning
- Automated browser testing frameworks spawning shell processes legitimately
- Enterprise software bundled with browser-initiated installers
- Security tools using osascript for automation
- Developer workflow tools that hook into browser processes
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
Unlock Pro Content
Get the full detection package for CVE-2025-43529 including response playbook, investigation guide, and atomic red team tests.