Detect Apple Multiple Products Buffer Overflow Exploitation (CVE-2026-20700) in Elastic Security
Detects exploitation attempts and post-exploitation activity related to CVE-2026-20700, a buffer overflow vulnerability (CWE-119) affecting multiple Apple products. This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild. Buffer overflow exploitation against Apple platforms may result in arbitrary code execution, privilege escalation, or sandbox escape.
MITRE ATT&CK
Elastic Detection Query
sequence by host.id with maxspan=2m
[process where host.os.type in ("macos", "ios") and
process.parent.name in ("Safari", "WebKit", "com.apple.WebKit.WebContent", "MobileSafari") and
process.name in ("sh", "bash", "zsh", "python", "python3", "osascript", "launchctl", "curl", "nc", "ncat")]
[any where event.category in ("network", "process") and
(network.direction == "egress" or
process.name in ("sh", "bash", "zsh", "python3", "osascript") and
process.args : ("*base64*", "*exec*", "*reverse*", "*shell*", "*wget*", "*curl*"))]EQL sequence detection for CVE-2026-20700 exploitation chain: suspicious child process spawned from Apple browser/webkit followed by network egress or further shell activity within a 2-minute window.
Data Sources
Required Tables
False Positives & Tuning
- Automated testing frameworks spawning processes from browser-driven test runners on macOS
- Browser-based development environments or IDEs that spawn terminal processes
- Legitimate developer workflow tools using WebKit engine that spawn system processes
- Electron-based applications that use WebKit internals and spawn child processes
Other platforms for CVE-2026-20700
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 WebKit Child Process Spawn (macOS)
Expected signal: EDR should log process creation event with parent process name matching 'com.apple.WebKit.WebContent' spawning 'bash' with shell commands. Network telemetry should show no external connections in this baseline test.
- Test 2Simulate Post-Exploitation Persistence via LaunchAgent (macOS)
Expected signal: File creation event in ~/Library/LaunchAgents/ with a plist filename mimicking Apple system components. EDR should log the file write and potentially the LaunchAgent registration.
- Test 3Simulate Exploit Attempt Network Callback (macOS)
Expected signal: Network connection attempt from curl process with unusual User-Agent string. In production scenario, this would be replaced with the WebKit process making the network connection directly.
- Test 4Heap Spray Pattern Simulation via Python (macOS/Linux)
Expected signal: Python process allocating large contiguous memory blocks in rapid succession. Memory allocation anomaly detection in EDR should generate telemetry showing large heap allocations.
Unlock Pro Content
Get the full detection package for CVE-2026-20700 including response playbook, investigation guide, and atomic red team tests.