CVE-2017-8685 in Windows
Summary
by MITRE
Windows GDI+ on Microsoft Windows Server 2008 SP2 and R2 SP1, and Windows 7 SP1 allows information disclosure by the way it discloses kernel memory addresses, aka "Windows GDI+ Information Disclosure Vulnerability". This CVE ID is unique from CVE-2017-8684 and CVE-2017-8688.
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Analysis
by VulDB Data Team • 01/12/2021
The vulnerability identified as CVE-2017-8685 represents a significant information disclosure flaw within the Windows Graphics Device Interface Plus component that affects multiple Windows operating systems including Windows Server 2008 SP2 and R2 SP1, as well as Windows 7 SP1. This vulnerability stems from how the GDI+ subsystem handles certain kernel memory operations during graphic processing tasks, creating an unintended pathway for attackers to extract sensitive kernel memory addresses. The flaw specifically manifests when the system processes certain graphic objects or rendering operations that trigger memory access patterns exposing kernel memory locations to user-mode applications. This type of information disclosure vulnerability falls under the CWE-200 category of "Information Exposure" and represents a critical concern for system security as it provides adversaries with valuable insights into the target system's memory layout and kernel structures.
The technical exploitation of this vulnerability occurs through carefully crafted graphic objects or rendering operations that cause the GDI+ subsystem to inadvertently expose kernel memory addresses through error messages, debug information, or memory dump contents. When legitimate applications process malformed graphic data or when specific rendering sequences are executed, the vulnerability allows for the leakage of kernel memory addresses that can be used to bypass security mechanisms such as address space layout randomization. This information disclosure can be particularly dangerous when combined with other exploitation techniques as it provides attackers with the exact memory locations of kernel structures, making subsequent exploitation attempts more precise and effective. The vulnerability demonstrates a fundamental flaw in the memory management and error handling procedures within the Windows GDI+ subsystem where proper bounds checking and memory isolation mechanisms are insufficient to prevent unauthorized memory access patterns.
The operational impact of CVE-2017-8685 extends beyond simple information disclosure as it creates a foundation for more sophisticated attacks that can leverage the leaked memory addresses to bypass modern security protections. Attackers can use the disclosed kernel memory addresses to perform advanced exploitation techniques including return-oriented programming attacks, kernel code execution, or privilege escalation operations that would otherwise be significantly more difficult to achieve. This vulnerability aligns with ATT&CK technique T1068 which covers "Local Privilege Escalation" and T1059 which addresses "Command and Scripting Interpreter" by providing the necessary information to craft more effective local attacks. The exposure of kernel memory addresses can also facilitate bypassing of exploit mitigations such as kernel address space layout randomization, making the system more vulnerable to subsequent exploitation attempts. Organizations running affected systems face significant risk as this vulnerability can be exploited remotely through various attack vectors including web browsers, email clients, or any application that processes graphic content.
Mitigation strategies for CVE-2017-8685 primarily involve applying the official Microsoft security patches released as part of the August 2017 security updates, which address the underlying memory handling issues within the GDI+ subsystem. System administrators should prioritize patch deployment across all affected Windows systems and implement proper network segmentation to limit potential attack surfaces. Additional protective measures include disabling unnecessary graphic processing capabilities, implementing strict application whitelisting policies, and monitoring for suspicious memory access patterns or error messages that might indicate exploitation attempts. The vulnerability also highlights the importance of regular security assessments and vulnerability scanning to identify similar memory management flaws in other system components. Organizations should consider implementing intrusion detection systems that can monitor for patterns consistent with information disclosure attacks and maintain comprehensive incident response procedures that account for the specific threat landscape created by such vulnerabilities. The remediation process should include thorough testing of patches in controlled environments before widespread deployment to ensure compatibility with existing applications and system configurations.