CVE-2021-30559: Google Chrome ANGLE RCE Vulnerability

CVE-2021-30559 Overview

CVE-2021-30559 is an out-of-bounds write vulnerability in the ANGLE (Almost Native Graphics Layer Engine) component of Google Chrome prior to version 91.0.4472.164. This memory corruption vulnerability allows a remote attacker to potentially exploit heap corruption via a crafted HTML page, enabling arbitrary code execution on the victim's system.

Critical Impact

Remote attackers can exploit this heap corruption vulnerability through malicious web pages to achieve code execution with the privileges of the Chrome browser process.

Affected Products

• Google Chrome versions prior to 91.0.4472.164
• Chromium-based browsers using the vulnerable ANGLE component
• All platforms running affected Chrome versions (Windows, macOS, Linux)

Discovery Timeline

• 2021-08-03 - CVE-2021-30559 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2021-30559

Vulnerability Analysis

This vulnerability is classified as CWE-787 (Out-of-bounds Write), a memory corruption issue affecting the ANGLE graphics abstraction layer in Google Chrome. ANGLE is responsible for translating OpenGL ES API calls to platform-specific graphics APIs, making it a critical component for rendering web content.

The out-of-bounds write condition allows an attacker to write data beyond the boundaries of allocated memory buffers on the heap. When successfully exploited, this can lead to heap corruption, enabling an attacker to overwrite critical memory structures and potentially achieve arbitrary code execution.

The attack requires user interaction—specifically, the victim must navigate to or be redirected to a maliciously crafted HTML page. Once the victim visits the page, the specially crafted content triggers the vulnerable code path in ANGLE, causing the out-of-bounds write condition.

Root Cause

The vulnerability stems from improper bounds checking in the ANGLE component when processing graphics-related operations. The lack of proper validation when writing to memory buffers allows data to be written beyond allocated boundaries, corrupting adjacent heap memory. This type of flaw typically occurs when array indices or buffer sizes are not properly validated against allocated memory regions.

Attack Vector

The attack is network-based and requires user interaction. An attacker must craft a malicious HTML page that triggers the vulnerable code path in ANGLE. The attack scenario typically involves:

1. Attacker creates a malicious web page containing crafted content designed to trigger the ANGLE vulnerability
2. Victim is lured to visit the page through phishing, malicious advertising, or compromised legitimate sites
3. The crafted content causes an out-of-bounds write in the ANGLE component
4. Heap corruption allows the attacker to potentially execute arbitrary code

The vulnerability manifests during graphics processing operations within the ANGLE component. When Chrome processes the malicious page content, improper memory handling leads to heap corruption. For detailed technical information, refer to the Chromium Bug Report #1219082.

Detection Methods for CVE-2021-30559

Indicators of Compromise

• Unusual Chrome browser crashes or memory corruption errors during web browsing
• Suspicious network connections originating from Chrome processes after visiting unknown websites
• Evidence of heap corruption or memory violation events in system logs

Detection Strategies

• Monitor Chrome version deployments across the enterprise to identify unpatched instances below 91.0.4472.164
• Deploy endpoint detection rules to identify anomalous Chrome process behavior including unexpected child processes or memory access patterns
• Implement web filtering to block known malicious domains that may be hosting exploit content

Monitoring Recommendations

• Enable crash reporting and analyze Chrome crash dumps for signs of ANGLE-related memory corruption
• Monitor for unusual Chrome renderer process behavior that may indicate exploitation attempts
• Review network traffic for connections to suspicious domains following Chrome browsing sessions

How to Mitigate CVE-2021-30559

Immediate Actions Required

• Update Google Chrome to version 91.0.4472.164 or later immediately across all systems
• Enable automatic Chrome updates to ensure timely application of security patches
• Consider deploying browser isolation solutions to reduce attack surface for web-based exploits
• Implement web content filtering to reduce exposure to potentially malicious pages

Patch Information

Google addressed this vulnerability in the stable channel update released in July 2021. The fix is included in Chrome version 91.0.4472.164 and all subsequent releases. Organizations should verify all Chrome installations are updated to this version or later.

For complete patch details, refer to the Google Chrome Releases Blog.

Workarounds

• Restrict access to untrusted websites through enterprise web filtering solutions
• Consider temporarily disabling hardware acceleration in Chrome settings to reduce ANGLE attack surface
• Deploy browser isolation technologies to execute web content in sandboxed environments

# Check Chrome version from command line (Windows)
"C:\Program Files\Google\Chrome\Application\chrome.exe" --version

# Check Chrome version from command line (Linux/macOS)
google-chrome --version

# Force Chrome update check
# Navigate to chrome://settings/help in browser