CVE-2017-8699 in Windows
Summary
by MITRE
Windows Shell in Microsoft Windows 7 SP1, Windows Server 2008 and R2 SP1, Windows 8.1 and Windows RT 8.1, Windows Server 2012 and R2, Windows 10 Gold, 1511, 1607, 1703, and Windows Server 2016 allows an attacker to run arbitrary code in the context of the current user, due to the way that Windows Shell validates file copy destinations, aka "Windows Shell Remote Code Execution Vulnerability".
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Analysis
by VulDB Data Team • 01/12/2021
The Windows Shell remote code execution vulnerability CVE-2017-8699 represents a critical security flaw in Microsoft Windows operating systems that affects multiple versions including Windows 7 SP1 through Windows 10 version 1703. This vulnerability resides within the Windows Shell component which is responsible for managing user interactions with the operating system through graphical interfaces and file operations. The flaw specifically manifests in how the Windows Shell validates file copy destinations, creating a pathway for attackers to execute arbitrary code with the privileges of the currently logged-in user. This type of vulnerability falls under the Common Weakness Enumeration category CWE-121, which deals with stack-based buffer overflows, and more specifically aligns with CWE-787, representing out-of-bounds writes that can occur when the system fails to properly validate input parameters. The vulnerability operates through a sophisticated attack vector that leverages the Windows Shell's handling of file operations, particularly when users interact with maliciously crafted file paths or destinations during copy operations.
The technical implementation of this vulnerability exploits the Windows Shell's insufficient validation mechanisms when processing file copy operations. Attackers can craft malicious file paths or manipulate file destination parameters in a way that causes the Windows Shell to execute unintended code sequences. When a user performs file operations such as copying files or moving items, the system's shell component processes these operations and validates the destination paths. The flaw occurs when the validation logic fails to properly sanitize or check the destination parameters, allowing attackers to inject malicious code that executes in the context of the current user session. This particular vulnerability enables privilege escalation attacks where malicious code can be executed with the same permissions as the legitimate user, potentially leading to full system compromise. The ATT&CK framework categorizes this vulnerability under T1059 for command and scripting interpreter and T1068 for exploit for privilege escalation, as attackers can leverage this weakness to gain elevated privileges and maintain persistent access to compromised systems.
The operational impact of CVE-2017-8699 is significant across enterprise environments and individual user systems, as it allows for remote code execution without requiring user interaction beyond normal file operations. This makes the vulnerability particularly dangerous because it can be exploited through various attack vectors including malicious email attachments, compromised websites, or infected removable media. The vulnerability affects a wide range of Windows versions, making it a substantial threat across different deployment scenarios from desktop environments to server infrastructure. Organizations running affected Windows versions face potential data breaches, system compromise, and unauthorized access to sensitive information. The attack surface is broad since the vulnerability can be triggered through normal user activities such as opening folders, copying files, or interacting with network shares. Security teams must consider this vulnerability as a critical threat requiring immediate attention, as it can be exploited by both sophisticated advanced persistent threat actors and less sophisticated malware authors. The vulnerability's exploitation capability aligns with ATT&CK techniques for initial access and execution, making it a preferred target for attackers seeking to establish footholds within networks.
Mitigation strategies for CVE-2017-8699 should include immediate deployment of Microsoft security patches and updates, as the vulnerability was addressed through the August 2017 security updates. Organizations should implement network segmentation and access controls to limit potential attack vectors, particularly focusing on preventing unauthorized file transfers and network shares from being exploited. The implementation of application whitelisting policies can help prevent execution of malicious code, while regular security monitoring should be enhanced to detect anomalous file operations or unusual user activities. System administrators should also consider disabling unnecessary file sharing features and implementing strict file permission controls to reduce the attack surface. Additionally, user education and awareness programs should emphasize the importance of avoiding suspicious file operations and being cautious with email attachments or downloads from untrusted sources. Security professionals should monitor for indicators of compromise related to this vulnerability and implement proper incident response procedures to quickly address any exploitation attempts. The vulnerability's classification under CWE-787 and its exploitation patterns align with standard security controls recommended for buffer overflow vulnerabilities, emphasizing the need for proper input validation and memory safety practices in system components.