CVE-2017-8651 in Internet Explorer
Summary
by MITRE
Internet Explorer in Microsoft Windows Server 2008 SP2 and Windows Server 2012 allows an attacker to execute arbitrary code in the context of the current user due to Internet Explorer improperly accessing objects in memory, aka "Internet Explorer Memory Corruption Vulnerability".
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Analysis
by VulDB Data Team • 11/05/2019
The vulnerability identified as CVE-2017-8651 represents a critical memory corruption flaw within Internet Explorer's handling of objects in memory, affecting Microsoft Windows Server 2008 SP2 and Windows Server 2012 systems. This issue stems from improper object management during memory operations, creating a pathway for remote code execution that operates with the privileges of the currently logged-in user. The vulnerability manifests when Internet Explorer processes certain web content that triggers malformed memory access patterns, potentially leading to arbitrary code execution without user interaction. The flaw falls under the category of memory corruption vulnerabilities as classified by CWE-125, which specifically addresses out-of-bounds read conditions that can result in unpredictable behavior and potential exploitation. The attack vector leverages the browser's rendering engine to manipulate memory structures, creating opportunities for attackers to inject malicious code that executes with the same privileges as the target user. This particular vulnerability is significant because it affects server environments where Internet Explorer may be used for administrative tasks or legacy applications, expanding the potential attack surface beyond typical client environments. The exploitation requires no special privileges to initiate the attack, making it particularly dangerous in enterprise settings where administrators might inadvertently browse malicious content or where users might be tricked into visiting compromised websites.
The technical implementation of this vulnerability involves Internet Explorer's JavaScript engine and memory management systems failing to properly validate object references during memory operations. When processing certain web content, the browser's memory allocator may not correctly handle object boundaries, leading to situations where attacker-controlled data can overwrite critical memory locations. This memory corruption can be exploited through techniques such as heap spraying or controlled memory layout manipulation to achieve code execution. The vulnerability is particularly concerning because it operates within the browser's security context, meaning that successful exploitation can bypass many traditional security controls that rely on user privilege boundaries. Attackers can craft malicious web pages that, when loaded in Internet Explorer, trigger the memory corruption condition and subsequently execute arbitrary code. The exploit development process typically involves understanding the specific memory layout and object structures within Internet Explorer's memory space to ensure successful code injection and execution. The flaw demonstrates how modern browser security mechanisms can be circumvented through subtle memory management errors that may not be immediately apparent during normal operation.
The operational impact of CVE-2017-8651 extends beyond simple code execution to encompass potential full system compromise within server environments. Since Windows Server 2008 SP2 and Windows Server 2012 are commonly used for enterprise applications and administrative tasks, successful exploitation can provide attackers with access to critical infrastructure resources. The vulnerability can be leveraged to establish persistent access, escalate privileges, or deploy additional malware components that can further compromise the affected systems. Organizations running these server versions face significant risk as the vulnerability can be exploited remotely without requiring user interaction, making it particularly dangerous in environments where servers are accessible from the internet. The attack can potentially lead to data exfiltration, service disruption, or lateral movement within the network if the compromised server has access to other systems or resources. Furthermore, the vulnerability's exploitation can result in the complete compromise of the server environment, especially when combined with other attack vectors or when the server is running applications with elevated privileges. The impact is amplified in enterprise environments where servers may host sensitive data or critical business applications, making this vulnerability a high-priority target for threat actors seeking to gain unauthorized access to organizational resources.
Mitigation strategies for CVE-2017-8651 should prioritize immediate patch application through Microsoft's security updates, as the vulnerability has been addressed in subsequent security releases. Organizations should implement browser hardening measures including disabling unnecessary browser features, implementing content security policies, and restricting access to potentially malicious websites through network-level controls. The deployment of web application firewalls and intrusion detection systems can help identify and block exploitation attempts targeting this vulnerability. Regular security assessments and vulnerability scanning should be conducted to identify systems running affected versions of Internet Explorer and ensure proper patch management. Network segmentation and access controls should be implemented to limit the potential impact of successful exploitation, particularly in server environments where administrative privileges may be present. Security awareness training for administrators and users can help prevent social engineering attacks that might leverage this vulnerability, while maintaining up-to-date threat intelligence feeds can provide early warning of exploitation attempts. Additionally, organizations should consider implementing application whitelisting policies to restrict execution of unauthorized code and ensure that only trusted applications can run on affected systems, reducing the attack surface for potential exploitation. The vulnerability aligns with ATT&CK techniques involving memory corruption and privilege escalation, emphasizing the need for comprehensive defensive measures that address both the immediate threat and broader security posture of affected environments.