CVE-2017-11862 in Edge
Summary
by MITRE
ChakraCore and Microsoft Edge in Windows 10 1709 and Windows Server, version 1709 allows an attacker to gain the same user rights as the current user, due to how the scripting engine handles objects in memory, aka "Scripting Engine Memory Corruption Vulnerability". This CVE ID is unique from CVE-2017-11836, CVE-2017-11837, CVE-2017-11838, CVE-2017-11839, CVE-2017-11840, CVE-2017-11841, CVE-2017-11843, CVE-2017-11846, CVE-2017-11858, CVE-2017-11859, CVE-2017-11861, CVE-2017-11866, CVE-2017-11869, CVE-2017-11870, CVE-2017-11871, and CVE-2017-11873.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 01/23/2021
The vulnerability identified as CVE-2017-11862 represents a critical memory corruption flaw within Microsoft's ChakraCore JavaScript engine and Microsoft Edge browser implementation. This issue affects Windows 10 version 1709 and Windows Server version 1709 systems, where the scripting engine fails to properly handle object memory management during execution. The flaw manifests when the ChakraCore engine processes certain JavaScript objects in memory, leading to unpredictable behavior that can be exploited by malicious actors. According to the Common Weakness Enumeration framework, this vulnerability maps to CWE-125, which describes out-of-bounds read conditions that occur when a program attempts to access memory beyond the boundaries of a valid buffer or object. The vulnerability's classification aligns with ATT&CK technique T1059.007, which covers script-based execution through JavaScript engines, making it particularly dangerous in modern browser environments where JavaScript is extensively used for web applications.
The technical exploitation of this memory corruption vulnerability enables attackers to achieve privilege escalation from standard user rights to full system privileges. When the ChakraCore engine encounters malformed or specially crafted JavaScript objects during memory operations, it fails to validate memory boundaries properly, potentially allowing memory corruption that can be leveraged for code execution. The attacker can manipulate the scripting engine's object handling mechanisms to overwrite memory locations, potentially leading to arbitrary code execution within the context of the current user. This type of vulnerability is particularly dangerous because it operates at the core engine level where JavaScript objects are managed, making it difficult to detect and prevent through traditional application-level security measures. The vulnerability's distinct nature from other related CVEs in the same year demonstrates that it involves a unique memory handling pattern that differs from the other scripting engine issues affecting the same software ecosystem.
The operational impact of CVE-2017-11862 extends beyond simple privilege escalation, as it creates a pathway for attackers to establish persistent access within affected systems. Once successfully exploited, the vulnerability allows adversaries to execute malicious code with the privileges of the compromised user account, potentially leading to complete system compromise if that account has elevated permissions. The vulnerability affects both desktop and server environments, making it particularly concerning for enterprise deployments where Windows Server 2016 and Windows 10 1709 are commonly used. Organizations running these affected versions face significant risk, as the vulnerability can be exploited through various attack vectors including malicious websites, email attachments, or web-based exploits. The memory corruption aspect means that exploitation can result in system instability or crashes, but more commonly leads to silent privilege escalation that can go undetected for extended periods, allowing attackers to maintain persistent access and conduct reconnaissance or data exfiltration activities.
Mitigation strategies for CVE-2017-11862 should include immediate deployment of Microsoft security updates and patches that address the underlying memory handling issues within ChakraCore. Organizations should also implement network-level protections such as web application firewalls and content filtering solutions to prevent access to malicious JavaScript content. Browser hardening measures including disabling unnecessary JavaScript features, implementing strict content security policies, and using sandboxing techniques can reduce the attack surface. Additionally, security monitoring should focus on detecting anomalous JavaScript execution patterns and memory access violations that might indicate exploitation attempts. The vulnerability's nature as a scripting engine memory corruption makes it particularly challenging to defend against through traditional network security controls, requiring a layered approach that includes both endpoint protection and network monitoring solutions. Regular security assessments and vulnerability scanning should be conducted to identify systems running affected versions of Windows and ensure timely patch deployment. According to Microsoft's security advisory, this vulnerability was addressed through cumulative updates released in August 2017, making patch management a critical component of remediation efforts for organizations affected by this issue.