External risk intelligence

Google Chrome Use-After-Free Vulnerability Allows Remote Exploitation.

CVE advisoryKnown Exploit

CVE-2021-37975

A vulnerability in Google Chrome's V8 engine could allow remote attackers to corrupt memory via a crafted HTML page. This may lead to system compromise and data loss. Organizations using affected versions should update their software promptly.

4Halo Surface Signal

Use After Free

Google Chrome

before 94.0.4606.7133343510.011.0

External exposure likelihood

Halo Surface Signal score for CVE-2021-37975

The vulnerability exists in the web browser's engine and is triggered by processing crafted HTML content. Because web browsers are routinely used to navigate the public internet and render arbitrary content from external websites, the attack surface is considered commonly exposed to internet-sourced content.

Horizon Alert

Summary of the vulnerability and why it matters

This vulnerability affects Google Chrome's V8 JavaScript engine. A flaw within this engine could permit attackers to corrupt memory. This corruption can lead to the potential compromise of systems and data.

Vulnerable component: V8 engine in Google Chrome
Core weakness: Memory corruption
Main business impact: Potential system and data compromise

Attack Path

How an attacker could exploit the issue

A remote attacker could exploit a use-after-free vulnerability in the V8 JavaScript engine to cause heap corruption. This could potentially lead to unauthorized control over affected systems. The vulnerability is triggered when a user visits a crafted HTML page.

Requires visiting a malicious page.
Attacker exploits heap corruption.
Results in potential system control.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability presents a significant risk due to its potential for widespread exploitation. Attackers with moderate technical skill could craft malicious web pages to trigger this issue. Successful exploitation could lead to severe data corruption and compromise system integrity. Given the nature of the vulnerability and its presence in widely used software, organizations should treat this with high urgency.

Attacker skill: Moderate
Access needed: None (remote)
Business risk: High, requires urgent patching

Priority actions

Operational Fix

Recommended remediation, mitigation, and detection steps

This vulnerability in the V8 engine of Google Chrome could allow attackers to corrupt system memory, potentially leading to further exploitation. Organizations utilizing affected versions of Chrome or systems incorporating the V8 engine should take immediate action to mitigate this risk. The identified vulnerability is categorized as high severity and has been observed in the wild, indicating a need for prompt attention.

Identify systems running affected browsers.
Restrict access to untrusted websites.
Update to the latest vendor-provided security patch.
Confirm the successful application of the fix.
Monitor for unusual system behavior.

Frequently asked questions

What is the primary function of the V8 engine within Google Chrome, and how does a use-after-free vulnerability impact its operation?

The V8 engine is Google Chrome's JavaScript engine responsible for executing JavaScript code. A use-after-free vulnerability, as seen in CVE-2021-37975, means the engine attempts to access memory after it has been freed, leading to heap corruption. This corruption can be exploited by attackers to potentially gain control over the affected system.

What specific weakness class is associated with CVE-2021-37975, and how does it enable exploitation?

CVE-2021-37975 is associated with the weakness class CWE-416, which denotes a 'Use-After-Free' vulnerability. This type of flaw allows an attacker to exploit a situation where a program continues to use a memory location after it has been deallocated, leading to heap corruption and potential code execution.

How can a remote attacker trigger heap corruption through a crafted HTML page, and is there any scope negation in this attack?

A remote attacker can trigger heap corruption by tricking a user into visiting a specially crafted HTML page. The V8 engine's vulnerability is exploited when processing this page, leading to the memory corruption. The scope is User (U) in the CVSS vector, meaning the vulnerability does not affect other security scopes, but successful exploitation grants control over the user's system.

What is the relevance of CVE-2021-37975, considering its presence in widely used browsers and potential for exploitation?

The relevance of CVE-2021-37975 is high because it affects Google Chrome, a widely used web browser. The vulnerability allows for remote exploitation via a crafted HTML page, meaning attackers do not need direct access to a system. Its classification as 'HIGH' severity and inclusion in the Known Exploited Vulnerabilities (KEV) catalog underscore the significant risk it poses.

What practical steps should organizations take to respond to the threat posed by this use-after-free vulnerability?

Organizations should immediately identify systems running affected versions of Google Chrome and apply the latest security patches provided by the vendor. It is also advisable to restrict user access to untrusted websites as a precautionary measure. Confirming the successful application of fixes and monitoring for unusual system behavior are crucial for ensuring the mitigation is effective.

References

Written by Nicholas Merritt

External-surface CVE analysis and Halo Surface Signal prioritization for Halo Threat Intelligence.