CVE-2017-8609 in Edge
Summary
by MITRE
Microsoft Internet Explorer in Microsoft Windows 10 Gold, 1511, 1607, and 1703, and Windows Server 2016 allow an attacker to execute arbitrary code in the context of the current user when the JavaScript engine fails to render when handling objects in memory in Microsoft Internet Explorer, aka "Scripting Engine Memory Corruption Vulnerability". This CVE ID is unique from CVE-2017-8596, CVE-2017-8610, CVE-2017-8618, CVE-2017-8619, CVE-2017-8595, CVE-2017-8601, CVE-2017-8603, CVE-2017-8604, CVE-2017-8605, CVE-2017-8606, CVE-2017-8607, CVE-2017-8608, and CVE-2017-8609.
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Analysis
by VulDB Data Team • 12/12/2022
The vulnerability described in CVE-2017-8609 represents a critical memory corruption issue within Microsoft Internet Explorer's scripting engine that affects multiple Windows operating system versions including Windows 10 Gold, 1511, 1607, and 1703, as well as Windows Server 2016. This flaw resides in the JavaScript engine's handling of memory objects during rendering operations, creating a pathway for remote code execution attacks. The vulnerability specifically manifests when the scripting engine fails to properly manage memory objects, leading to unpredictable behavior that can be exploited by malicious actors. The issue is categorized under CWE-125 as an out-of-bounds read condition, which directly relates to improper memory management within the browser's execution environment. This vulnerability falls under the ATT&CK technique T1059.007 for Windows Command Shell and T1059.001 for Command and Scripting Interpreter, as attackers can leverage the compromised browser to execute malicious commands.
The technical exploitation of this vulnerability occurs when Internet Explorer processes JavaScript code that triggers memory corruption during object rendering operations. Attackers can craft malicious web pages that, when loaded in Internet Explorer, cause the browser's scripting engine to access memory locations outside the intended boundaries. This memory corruption can result in arbitrary code execution with the privileges of the current user, effectively allowing attackers to bypass standard security controls. The flaw is particularly dangerous because it operates within the browser's trusted execution environment, meaning that successful exploitation does not require additional privilege escalation. The vulnerability demonstrates characteristics of a heap-based buffer overflow, where the scripting engine's memory management fails to properly validate object boundaries during JavaScript execution. This type of vulnerability is classified as a use-after-free or memory corruption issue that can be triggered through carefully constructed JavaScript code.
The operational impact of CVE-2017-8609 extends beyond simple remote code execution, as it represents a significant threat vector for advanced persistent threats and zero-day attacks. Organizations running affected versions of Windows are particularly vulnerable because the exploit can be delivered through standard web browsing activities, making it difficult to detect and prevent. The vulnerability's exploitation requires minimal user interaction, typically just visiting a malicious website or clicking on a malicious link in an email. This makes it highly attractive to threat actors who can leverage it for phishing campaigns, drive-by downloads, and other social engineering attacks. The impact is amplified by the fact that many enterprise environments still run older versions of Windows, and the vulnerability affects the default browser on these systems, creating a wide attack surface. Security researchers have noted that this vulnerability can be combined with other exploits to create more sophisticated attack chains, potentially leading to full system compromise and lateral movement within networks.
Mitigation strategies for CVE-2017-8609 should focus on immediate patch management and browser hardening measures. Microsoft released security updates for this vulnerability through the August 2017 security bulletin, which should be deployed immediately across all affected systems. Organizations should implement browser isolation techniques and consider using alternative browsers such as Microsoft Edge or Chrome as temporary measures. Network-based mitigations include implementing web application firewalls and content filtering systems that can detect and block malicious JavaScript patterns. Additionally, users should be educated about the risks of visiting untrusted websites and clicking on suspicious links, as social engineering remains a primary attack vector for exploiting this vulnerability. Security teams should also monitor for indicators of compromise related to this vulnerability, including unusual network traffic patterns and system behavior that might suggest exploitation attempts. The vulnerability highlights the importance of maintaining up-to-date security patches and demonstrates how browser-based vulnerabilities can serve as initial access vectors for broader security breaches.