CVE-2021-38005 in Chrome
Summary
by MITRE • 12/23/2021
Use after free in loader in Google Chrome prior to 96.0.4664.45 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.
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Analysis
by VulDB Data Team • 12/26/2021
The vulnerability identified as CVE-2021-38005 represents a critical use-after-free flaw within the loader component of Google Chrome browsers. This issue affects versions prior to 96.0.4664.45 and allows remote attackers to potentially exploit heap corruption through maliciously crafted HTML pages. The vulnerability stems from improper memory management during the loading process where freed memory locations are accessed after being deallocated, creating opportunities for arbitrary code execution. The loader component is responsible for handling various web resources and script execution, making it a prime target for exploitation in web-based attacks. This particular flaw demonstrates the dangerous implications of memory safety issues in modern browser architectures where multiple components interact dynamically during page rendering and execution.
The technical implementation of this use-after-free vulnerability occurs when the browser's loader processes certain HTML elements or scripts that trigger memory deallocation followed by subsequent access to the same memory locations. The flaw specifically manifests during the handling of crafted HTML content that causes the loader to free memory resources while other execution paths still reference those locations. This creates a race condition where memory corruption can be exploited to overwrite critical data structures or function pointers, ultimately allowing attackers to execute malicious code with the privileges of the browser process. The vulnerability's impact is amplified by the fact that it requires no user interaction beyond visiting a malicious webpage, making it particularly dangerous in phishing campaigns or drive-by download scenarios. The flaw falls under CWE-416, which specifically addresses use-after-free conditions in software development practices.
The operational impact of CVE-2021-38005 extends beyond simple browser exploitation to encompass broader security implications for web-based environments. Attackers can leverage this vulnerability to bypass modern security mitigations such as address space layout randomization and data execution prevention mechanisms. The heap corruption introduced by this flaw can potentially be chained with other vulnerabilities to achieve privilege escalation or persistent access to user systems. Security researchers have noted that this vulnerability aligns with ATT&CK technique T1059.001, which involves the execution of malicious code through web-based attack vectors. The remote exploitation capability makes this vulnerability particularly concerning for enterprise environments where users may inadvertently visit compromised websites, and for organizations that do not maintain up-to-date browser versions. The vulnerability demonstrates the ongoing challenges in maintaining memory safety in complex browser architectures that must handle diverse and untrusted web content.
Mitigation strategies for CVE-2021-38005 primarily focus on immediate browser updates to versions 96.0.4664.45 and later, which contain the necessary patches to address the memory management flaw. Organizations should implement comprehensive patch management policies that ensure all browser installations are kept current with security updates. Additional protective measures include deploying web application firewalls and content filtering solutions that can detect and block malicious HTML content. Browser hardening techniques such as enabling sandboxing, disabling unnecessary browser features, and implementing strict content security policies can further reduce the attack surface. Security teams should monitor for exploitation attempts through network traffic analysis and endpoint detection systems that can identify suspicious memory access patterns. The vulnerability also underscores the importance of regular security assessments and penetration testing to identify similar memory safety issues in other browser components or web applications. Organizations should consider implementing automated vulnerability scanning tools that can detect outdated browser versions and flag potential exposure to known vulnerabilities.