CVE-2017-8524 in Internet Explorer
Summary
by MITRE
Microsoft browsers in Microsoft Windows 7 SP1, Windows Server 2008 R2 SP1, Windows 8.1 and Windows RT 8.1, Windows Server 2012 and R2, Windows 10 Gold, 1511, 1607, and 1703, and Windows Server 2016 allow an allow an attacker to execute arbitrary code in the context of the current user when the JavaScript engines fail to render when handling objects in memory in Microsoft browsers, aka "Scripting Engine Memory Corruption Vulnerability". This CVE ID is unique from CVE-2017-8517 and CVE-2017-8522.
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Analysis
by VulDB Data Team • 12/27/2020
The vulnerability described in CVE-2017-8524 represents a critical memory corruption flaw within Microsoft's scripting engines that affects multiple versions of the windows operating system and its associated browsers. This vulnerability specifically targets the JavaScript engines used in Microsoft browsers including Internet Explorer and Microsoft Edge across various windows versions from windows 7 through windows 10 version 1703, as well as windows server 2008 r2, 2012, 2012 r2, and 2016. The flaw occurs when these scripting engines fail to properly handle objects in memory during rendering processes, creating a condition where malicious code can be executed with the privileges of the currently logged-in user. This type of vulnerability falls under the category of memory corruption issues that are particularly dangerous because they can lead to complete system compromise when exploited by attackers. The vulnerability is classified as a scripting engine memory corruption vulnerability, which means it specifically targets the underlying memory management systems that handle javascript execution and rendering of web content. The flaw allows for arbitrary code execution in the context of the current user, making it particularly concerning for enterprise environments where users may have elevated privileges or access to sensitive data.
The technical nature of this vulnerability stems from improper memory handling within the javascript engines of Microsoft browsers, where the engines fail to properly validate or manage memory objects during rendering operations. When a malicious web page or document is processed, the vulnerable javascript engine does not correctly handle the memory management of certain objects, leading to memory corruption that can be leveraged by attackers to execute malicious code. This memory corruption typically occurs through buffer overflows or use-after-free conditions where the engine attempts to access memory that has already been freed or write beyond allocated memory boundaries. The vulnerability is particularly insidious because it can be triggered through web browsing activities without requiring any special privileges or user interaction beyond visiting a malicious website or opening a malicious document. The exploitation process involves crafting specific javascript code or document content that forces the vulnerable engine to corrupt memory in a way that allows attacker-controlled code to be executed. This type of vulnerability is classified as a cwe-121 heap-based buffer overflow according to the common weakness enumeration catalog, which specifically addresses issues related to improper handling of memory allocation and deallocation in software applications. The attack surface is broad since it affects multiple windows versions and browser engines, making it a prime target for mass exploitation campaigns.
The operational impact of CVE-2017-8524 is severe and far-reaching across enterprise networks and individual user systems. Successful exploitation of this vulnerability can result in complete system compromise, allowing attackers to execute arbitrary code with the privileges of the current user, which often translates to domain-level access in enterprise environments. The vulnerability can be leveraged for privilege escalation attacks, where attackers might gain access to administrative accounts or sensitive system resources. Organizations running affected windows versions are at significant risk since the vulnerability can be exploited through standard web browsing activities, making it difficult to prevent through traditional network security measures. The impact extends beyond individual system compromise to include potential data exfiltration, lateral movement within networks, and establishment of persistent backdoors. This vulnerability is particularly dangerous in corporate environments where users frequently browse the internet and may inadvertently encounter malicious content. The attack vector through web browsers makes it challenging to defend against since it requires constant updates and patches to address the underlying memory management issues. The vulnerability can also be used in combination with other exploits to create more sophisticated attack chains that can bypass security controls and access critical infrastructure components. According to the attack technique catalog, this vulnerability maps to techniques involving remote code execution through browser exploitation, which is categorized under attack technique t1203 and t1059, representing the exploitation of remote services and the use of scripting languages for execution.
Mitigation strategies for CVE-2017-8524 should include immediate deployment of microsoft security updates and patches that address the memory corruption issues in the javascript engines. Organizations should implement comprehensive patch management processes to ensure all affected windows systems receive the necessary updates promptly. Browser isolation techniques and enhanced security configurations can provide additional protection layers, including disabling javascript in certain contexts or implementing more restrictive security policies. Network segmentation and monitoring systems should be deployed to detect anomalous behavior that might indicate exploitation attempts. Regular security assessments and vulnerability scanning should be conducted to identify systems that may not have received the necessary patches. The implementation of security controls such as application whitelisting and exploit prevention tools can help reduce the risk of exploitation. Additionally, user education and awareness programs should be established to train personnel on recognizing potentially malicious web content and avoiding suspicious websites. Microsoft recommends implementing the security updates as soon as they become available and maintaining updated security configurations across all affected systems. The vulnerability requires a layered approach to security since it can be exploited through multiple vectors and may be combined with other techniques to achieve more significant impact. Organizations should also consider implementing intrusion detection systems that can identify the specific patterns of exploitation associated with this vulnerability and alert security teams to potential attacks. The remediation process should include verification that patches have been properly applied and that systems are no longer vulnerable to the memory corruption conditions that allow arbitrary code execution.