CVE-2020-27918

What it actually does

Use-after-free condition in memory management during processing of malicious web content that can result in arbitrary code execution.

Why it matters to the business

Attackers can gain full control of affected devices, risking data theft, surveillance, or ransomware deployment; high ecosystem prevalence increases exposure for organizations using the impacted software.

How an attack unfolds

An attacker delivers maliciously crafted web content that triggers the use-after-free flaw; named threat actors including Candiru have leveraged similar Apple WebKit issues for remote code execution.

How to fix it

Update to macOS Big Sur 11.0.1, iOS 14.2 / iPadOS 14.2, watchOS 7.1, tvOS 14.2, Safari 14.0.1, iCloud for Windows 11.5, iTunes 12.11 for Windows or later; apply the listed fixed commits for python-pillow/pillow.

How to confirm the fix worked

Verify installed versions match or exceed the fixed releases and confirm absence of the vulnerable memory handling code paths via patch review or vendor advisories.

Typical attack path

1. Deliver malicious web content via browser or related application
2. Trigger use-after-free through crafted input
3. Achieve arbitrary code execution in the process context
4. Establish persistence or exfiltrate data

How to detect it

Review web browser process crash logs, memory dumps, and network traffic for indicators of malicious content delivery; correlate with known threat actor TTPs associated with Apple WebKit exploitation.

What your security team should do

• Prioritize patching all listed Apple products before the CISA due date if applicable
• Monitor EPSS trend and threat actor activity for increased urgency
• Block untrusted web content sources until updates are deployed