CVE-2017-8557 in Windows
Summary
by MITRE
Windows System Information Console in Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, Windows 10 Gold, 1511, 1607, 1703, and Windows Server 2016 allows a information disclosure vulnerability improperly parses XML input containing a reference to an external entity, aka "Windows System Information Console Information Disclosure Vulnerability".
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 12/31/2020
The vulnerability identified as CVE-2017-8557 represents a critical information disclosure flaw within the Windows System Information Console component that affects multiple Windows operating systems including legacy versions like Windows Server 2008 and Windows 7 through modern releases such as Windows 10 version 1703 and Windows Server 2016. This vulnerability stems from improper XML parsing mechanisms within the system information console that fails to adequately validate or sanitize external entity references in XML input streams. The flaw operates at the core of XML processing libraries that Windows utilizes for parsing system information files, creating a pathway for malicious actors to extract sensitive data from targeted systems. The vulnerability is classified under CWE-611, which specifically addresses Improper Restriction of XML External Entity Reference, making it a direct descendant of well-known XML external entity processing flaws that have plagued software systems for decades.
The technical exploitation of this vulnerability occurs when the Windows System Information Console processes XML files that contain malformed external entity declarations. When the console encounters such input, it improperly resolves these external references without proper validation, allowing an attacker to craft malicious XML documents that can trigger information disclosure through various means including file system access, network resource enumeration, or even privilege escalation pathways. The attack vector typically involves delivering a specially crafted XML file that references external resources, which when processed by the vulnerable console component, can expose system information that should remain confidential. This processing behavior aligns with ATT&CK technique T1059.007 for Windows Command Shell execution and T1082 for System Information Discovery, as the vulnerability enables adversaries to gather sensitive system metadata that can inform further attack planning.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can provide attackers with critical system intelligence that facilitates more sophisticated attacks. An attacker who successfully exploits this vulnerability can potentially access system configuration details, user account information, network settings, and other sensitive metadata that would normally be protected within the Windows operating system. The vulnerability affects both server and client operating systems, making it particularly dangerous in enterprise environments where Windows Server 2008 and 2012 R2 systems may still be operational. The affected systems include Windows 7 SP1, Windows 8.1, Windows Server 2008 SP2, Windows Server 2012 R2, and various Windows 10 versions, representing a broad attack surface that spans multiple generations of Microsoft operating systems. This widespread impact makes the vulnerability particularly concerning for organizations with legacy system deployments that may not have received timely security updates.
Mitigation strategies for CVE-2017-8557 should prioritize immediate patch deployment through Microsoft's security updates, specifically addressing the XML parsing vulnerabilities in the Windows System Information Console component. Organizations should implement network segmentation and access controls to limit exposure of systems running vulnerable versions of Windows, particularly those that process untrusted XML content. Security monitoring should be enhanced to detect unusual XML processing activities or attempts to access system information through the console component. The implementation of XML parsing restrictions that prevent external entity resolution should be considered as a defensive measure, aligning with industry best practices for XML security as outlined in OWASP XML Security guidelines. Additionally, system administrators should conduct comprehensive vulnerability assessments to identify all systems running affected Windows versions and prioritize remediation efforts based on risk exposure and business criticality. Regular security awareness training should emphasize the importance of avoiding untrusted XML content and the potential consequences of processing malformed input streams that could trigger this type of vulnerability.