CVE-2024-6988: Google Chrome Use After Free Vulnerability

CVE-2024-6988 Overview

CVE-2024-6988 is a Use After Free vulnerability in the Downloads component of Google Chrome on iOS. This memory corruption flaw exists in versions prior to 127.0.6533.72 and allows a remote attacker to potentially exploit heap corruption via a crafted HTML page. The vulnerability has been classified with high severity by the Chromium security team.

Critical Impact

Remote attackers can exploit heap corruption through malicious web pages, potentially leading to arbitrary code execution, data theft, or complete browser compromise on iOS devices.

Affected Products

• Google Chrome for iOS (versions prior to 127.0.6533.72)
• Apple iPhone OS (as the underlying platform)

Discovery Timeline

• August 6, 2024 - CVE-2024-6988 published to NVD
• August 7, 2024 - Last updated in NVD database

Technical Details for CVE-2024-6988

Vulnerability Analysis

This vulnerability is classified as CWE-416 (Use After Free), a type of memory corruption vulnerability where the application continues to use a memory pointer after the associated memory has been freed. In the context of Google Chrome's Downloads functionality on iOS, this occurs when the browser improperly manages memory during download operations.

When a user interacts with download-related functionality on a maliciously crafted HTML page, the browser may free memory that is subsequently accessed, leading to heap corruption. This can result in unpredictable behavior including potential code execution within the browser's context.

The vulnerability requires user interaction—specifically, a user must visit a malicious webpage that triggers the vulnerable code path in the Downloads component. Once triggered, an attacker could potentially gain control over the heap memory layout and achieve arbitrary code execution.

Root Cause

The root cause of CVE-2024-6988 lies in improper memory lifecycle management within Chrome's Downloads component on iOS. The vulnerable code path fails to properly track the state of dynamically allocated memory objects, resulting in a dangling pointer condition. When this dangling pointer is subsequently dereferenced, it accesses freed memory, causing heap corruption that can be exploited by attackers.

Attack Vector

The attack vector is network-based and requires user interaction. An attacker must craft a malicious HTML page designed to trigger the vulnerable code path in Chrome's Downloads component. The attack scenario typically involves:

1. An attacker hosts a malicious webpage containing specially crafted HTML content
2. A victim using Google Chrome on iOS navigates to the malicious page
3. The page triggers download-related functionality that exploits the Use After Free condition
4. The resulting heap corruption can be leveraged for arbitrary code execution

The vulnerability can be exploited remotely without requiring any privileges on the target system, though user interaction (visiting the malicious page) is necessary for successful exploitation.

Detection Methods for CVE-2024-6988

Indicators of Compromise

• Unusual Chrome process crashes or unexpected browser restarts on iOS devices
• Memory access violations or heap corruption errors in browser diagnostics
• Unexpected download activity or download prompts from untrusted websites
• Abnormal network traffic patterns indicating exploitation attempts

Detection Strategies

• Monitor for Google Chrome versions prior to 127.0.6533.72 across managed iOS devices
• Implement web filtering to block known malicious domains distributing exploit pages
• Deploy endpoint detection solutions capable of identifying heap corruption exploitation patterns
• Review browser crash reports for indicators of memory corruption in the Downloads component

Monitoring Recommendations

• Establish baseline browser behavior and alert on anomalous download-related activity
• Configure centralized logging for browser crash events across enterprise iOS devices
• Monitor for threat intelligence feeds related to Chrome exploitation campaigns
• Implement network-level detection for malicious HTML content delivery

How to Mitigate CVE-2024-6988

Immediate Actions Required

• Update Google Chrome on all iOS devices to version 127.0.6533.72 or later immediately
• Enable automatic browser updates to ensure timely patching of future vulnerabilities
• Educate users about the risks of visiting untrusted websites
• Consider implementing web filtering to restrict access to potentially malicious content

Patch Information

Google has released a security update addressing this vulnerability in Chrome version 127.0.6533.72 for iOS. Organizations should prioritize updating all managed Chrome installations to this version or later. The fix addresses the improper memory management in the Downloads component that led to the Use After Free condition.

For detailed information about the security update, refer to the Google Chrome Desktop Update announcement. Technical details can be found in the Chromium Issue Tracker Entry.

Workarounds

• Temporarily disable automatic downloads in Chrome settings until the patch can be applied
• Use alternative browsers on iOS devices until Chrome can be updated
• Implement strict web filtering policies to minimize exposure to untrusted content
• Consider deploying mobile device management (MDM) solutions to enforce browser version compliance