CVE-2018-0878 in Windows
Summary
by MITRE
Windows Remote Assistance in Microsoft Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1 and RT 8.1, Windows Server 2012 and R2, Windows 10 Gold, 1511, 1607, 1703, and 1709, Windows Server 2016 and Windows Server, version 1709 allows an information disclosure vulnerability due to how XML External Entities (XXE) are processed, aka "Windows Remote Assistance Information Disclosure Vulnerability".
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Analysis
by VulDB Data Team • 04/05/2025
The Windows Remote Assistance feature in Microsoft operating systems presents a significant information disclosure vulnerability through improper handling of XML External Entities. This vulnerability affects a broad range of Microsoft products spanning multiple versions from Windows Server 2008 through Windows 10 versions 1511, 1607, 1703, and 1709, as well as Windows Server 2016 and Server version 1709. The flaw resides in how the system processes XML data during remote assistance sessions, creating an attack surface that adversaries can exploit to gain unauthorized access to sensitive information. This vulnerability represents a classic example of XML External Entity processing issues that have been documented in numerous security advisories and standards.
The technical root cause of this vulnerability stems from the improper validation and processing of XML input within the Windows Remote Assistance functionality. When remote assistance sessions are established, the system processes XML data containing external entity references that can be manipulated by attackers. This processing behavior creates an information disclosure condition where maliciously crafted XML content can cause the system to reveal internal file paths, system information, or other sensitive data. The vulnerability aligns with CWE-611, which specifically addresses improper restriction of XML external entity references, and demonstrates the dangerous implications when XML parsers fail to properly sanitize external entity declarations. The attack vector involves an attacker crafting specially formatted XML content that, when processed by the vulnerable Windows Remote Assistance component, triggers unintended information disclosure behavior.
The operational impact of this vulnerability extends beyond simple information disclosure to potentially enable more sophisticated attacks within compromised environments. An attacker who successfully exploits this vulnerability could obtain sensitive system information, including file system details, network configurations, or other data that could aid in further exploitation attempts. This information disclosure could serve as a stepping stone for additional attacks, potentially leading to privilege escalation or lateral movement within a network. The vulnerability affects both server and client operating systems, meaning that either endpoint in a remote assistance session could be compromised, creating a risk that extends to organizations using Windows Remote Assistance for legitimate support operations. The widespread nature of affected versions means that organizations with legacy systems or extended support environments face significant exposure.
Mitigation strategies for this vulnerability require a multi-layered approach combining immediate patch management with network-level controls and operational security measures. Microsoft released security updates that address the XXE processing issue in affected Windows versions, and organizations should prioritize deployment of these patches across all affected systems. Network segmentation and access controls should be implemented to limit exposure of systems running Windows Remote Assistance, particularly in environments where remote assistance is not strictly required. Security monitoring should include detection of unusual XML processing activities or attempts to access system resources through remote assistance sessions. The ATT&CK framework categorizes this vulnerability under T1059 for remote access tools and T1046 for network service scanning, indicating that exploitation could be detected through network traffic analysis and system monitoring. Organizations should also consider disabling Windows Remote Assistance functionality when not actively needed, as this represents the most effective immediate mitigation strategy for environments where patch deployment cannot be immediately implemented.