CVE-2020-3899

What it actually does

Memory consumption flaw in WebKit allows remote attackers to trigger arbitrary code execution via crafted content due to improper memory handling.

Why it matters to the business

Attackers could gain control of user devices across the Apple ecosystem, resulting in data theft, unauthorized access, or further compromise of personal and enterprise systems that remain unpatched after years of availability.

How an attack unfolds

An attacker crafts malicious web content that triggers excessive memory consumption in WebKit, leading to memory corruption and subsequent arbitrary code execution when rendered in Safari, iCloud, iTunes, or other affected Apple products.

How to fix it

Upgrade affected products to the fixed releases: iOS 13.4 and iPadOS 13.4, tvOS 13.4, watchOS 6.2, Safari 13.1, iTunes for Windows 12.10.5, iCloud for Windows 10.9.3, or iCloud for Windows 7.18. Disable automatic rendering of web content from untrusted sources until updates are applied.

How to confirm the fix worked

Confirm installed versions of Safari, iOS, iPadOS, tvOS, watchOS, iTunes, and iCloud match or exceed the listed fixed releases; test rendering of known trigger content in isolated environments to verify no crash or unexpected memory growth occurs.

Typical attack path

1. Craft and host malicious webpage exploiting WebKit memory handling
2. Lure victim to visit the page via phishing or compromised site
3. Trigger memory corruption leading to code execution in the browser or related process
4. Establish persistence or exfiltrate data on the compromised device

How to detect it

Inspect system and application logs for WebKit crashes or excessive memory allocation events around the time of web browsing; correlate with browser history for suspicious external domains.

What your security team should do

• Prioritize patching all listed Apple products immediately given the remote code execution impact and long public exposure
• Block or sandbox WebKit-based browsing for high-risk users until updates are deployed
• Review endpoint logs for WebKit process anomalies and integrate version checks into asset management