CVE-2021-33741 in Edge
Summary
by MITRE • 06/09/2021
Microsoft Edge (Chromium-based) Elevation of Privilege Vulnerability
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Analysis
by VulDB Data Team • 06/11/2021
This vulnerability exists in Microsoft Edge browser when it fails to properly handle objects in memory during certain operations, leading to an elevation of privilege condition. The flaw occurs within the browser's chromium-based rendering engine where improper memory management allows an attacker to manipulate object references and execute arbitrary code with elevated privileges. The vulnerability specifically affects how Edge handles certain JavaScript objects and their interaction with the underlying memory allocation system, creating a path for privilege escalation from standard user context to system-level access. This issue represents a critical security gap that undermines the browser's security model and could be exploited by malicious actors to gain unauthorized system control.
The technical implementation of this vulnerability stems from inadequate validation of object references within Edge's JavaScript engine and memory management subsystem. When processing specific web content that triggers memory allocation patterns, the browser fails to properly validate object lifetimes and memory boundaries, allowing for memory corruption that can be exploited to execute malicious code. This type of vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-125, which addresses out-of-bounds read errors. The flaw enables attackers to manipulate memory layout and object references to bypass security restrictions that normally protect system resources and user data. Attackers can leverage this condition to execute code with the privileges of the target system, potentially leading to complete system compromise.
The operational impact of CVE-2021-33741 is severe and far-reaching within enterprise and individual computing environments. Successful exploitation allows attackers to bypass standard browser security controls and gain system-level privileges, enabling them to install malware, access sensitive data, modify system configurations, or establish persistent backdoors. The vulnerability affects all versions of Microsoft Edge that are based on the chromium engine, including those running on Windows 10 and Windows 11 operating systems. This creates a significant risk for organizations where Edge is the primary browser, as attackers can leverage this vulnerability to compromise endpoints and potentially move laterally through networks. The attack vector typically involves phishing campaigns or compromised websites that deliver malicious content designed to trigger the specific memory manipulation conditions.
Mitigation strategies for this vulnerability require immediate patch management and layered security approaches. Microsoft has released security updates that address the memory handling flaws in Edge's chromium engine, and organizations should prioritize applying these patches across all affected systems. Network security controls such as web application firewalls and content filtering solutions can help reduce the risk of exploitation by blocking malicious content delivery. Browser hardening measures including disabling unnecessary JavaScript features, implementing strict content security policies, and using sandboxing mechanisms can provide additional protection. Organizations should also implement monitoring solutions to detect anomalous behavior that might indicate exploitation attempts, and conduct regular security assessments to identify potential attack surfaces. The vulnerability demonstrates the importance of maintaining up-to-date browser security patches and implementing defense-in-depth strategies to protect against sophisticated exploitation techniques that target browser security boundaries. This vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1068 for exploit for privilege escalation, highlighting the need for comprehensive endpoint protection and security monitoring.