CVE-2018-0886 in Windows
Summary
by MITRE
The Credential Security Support Provider protocol (CredSSP) 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 a remote code execution vulnerability due to how CredSSP validates request during the authentication process, aka "CredSSP Remote Code Execution Vulnerability".
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Analysis
by VulDB Data Team • 10/25/2025
The CVE-2018-0886 vulnerability represents a critical remote code execution flaw within Microsoft's Credential Security Support Provider protocol implementation across multiple operating systems including Windows Server 2008, Windows 7, Windows 8.1, and various Windows 10 versions. This vulnerability specifically targets the authentication process where CredSSP fails to properly validate incoming requests during the credential negotiation phase, creating an exploitable condition that allows attackers to execute arbitrary code on affected systems. The flaw exists in the way the protocol handles authentication tokens and validation sequences, particularly when processing certain credential structures that bypass normal security checks.
The technical root cause of this vulnerability lies in improper input validation within the CredSSP authentication mechanism, which operates under CWE-20 - Improper Input Validation. When a remote attacker sends specially crafted authentication requests, the system fails to properly validate the credential data, allowing malformed or unexpected inputs to be processed without adequate security checks. This weakness enables attackers to manipulate the authentication flow and potentially escalate privileges or execute malicious code. The vulnerability is particularly dangerous because CredSSP is commonly used in remote desktop services and other authentication scenarios where secure credential handling is critical.
The operational impact of CVE-2018-0886 extends significantly beyond standard remote code execution capabilities, as it affects core Windows authentication infrastructure that is fundamental to enterprise security operations. Organizations relying on Remote Desktop Protocol connections, Windows Remote Management, or other services utilizing CredSSP are particularly vulnerable to exploitation. Attackers can leverage this vulnerability to gain unauthorized access to systems, potentially leading to full system compromise, data exfiltration, or lateral movement within networks. The vulnerability affects systems that use CredSSP for authentication, which includes many enterprise environments that depend on remote desktop services and Windows-based authentication systems, making it a high-priority target for threat actors.
Mitigation strategies for CVE-2018-0886 should focus on immediate patch deployment through Microsoft's security updates, which address the core validation issues in the CredSSP implementation. Organizations should also implement network segmentation and access controls to limit exposure of systems using CredSSP authentication, particularly those accessible from untrusted networks. Security teams should monitor for exploitation attempts through network traffic analysis and implement logging controls to detect anomalous authentication patterns that may indicate exploitation attempts. The vulnerability aligns with ATT&CK technique T1075 - Pass the Hash and T1566 - Phishing, as attackers can leverage the compromised authentication system to maintain persistence or escalate privileges within the network environment. Additionally, organizations should consider disabling CredSSP where possible and implementing alternative authentication methods that do not expose similar validation weaknesses, as recommended in Microsoft's security best practices for preventing credential-based attacks.