RDP access Archives

Winsage

October 9, 2025

Tested: Why Remote Desktop Protocol (RDP) rejects Microsoft account logins

Some users are experiencing issues with Remote Desktop Protocol (RDP) rejecting Microsoft Account (MSA) credentials, displaying an error message about invalid credentials. This problem can arise from various technical factors, including: - Credential validation failures due to issues with Microsoft server interactions. - Problems with secure channel negotiation during the authentication process. - Time synchronization or DNS resolution issues affecting credential verification. - Misconfigured credential policies that block MSA logins over RDP. - Network-Level Authentication requirements that may hinder access if the MSA does not meet security standards like two-factor authentication. - Account restrictions or conditional access policies that impose specific compliance requirements. - Corruption of the user profile associated with the MSA. - Software conflicts or updates, particularly with recent Cumulative Updates or third-party security tools. To address MSA authentication failures, creating a local administrator account on the target machine can serve as a workaround for RDP access. Some users have noted that while most PCs function well with an MSA, certain systems require a local account for successful connections, particularly on Windows versions 24H2 and 25H2 within Insider Preview builds.

Tech Optimizer

August 8, 2025

Cyberattackers Leverage Trusted Drivers to Disable Antivirus Software and Bypass Security Protocols

A cyberattack on a Brazilian enterprise involved the use of legitimate, digitally signed drivers to disable antivirus solutions and deploy MedusaLocker ransomware. The attackers executed a Bring Your Own Vulnerable Driver (BYOVD) attack by exploiting the ThrottleStop.sys driver, which has a critical vulnerability (CVE-2025-7771) allowing unauthorized memory access. They compromised an SMTP server using valid RDP credentials, extracted user credentials with Mimikatz, and moved laterally across the network. The attackers uploaded and executed an AV killer program and a renamed version of the driver, terminating antivirus processes to facilitate ransomware deployment. The malware targeted major antivirus vendors and employed kernel-level commands to eliminate security processes. Recommendations for defense include multi-factor authentication, hardening RDP access, and implementing layered security measures.

Winsage

April 30, 2025

Windows RDP lets you log in using revoked passwords. Microsoft is OK with that.

The ability to use a revoked password for Remote Desktop Protocol (RDP) access on Windows machines linked to Microsoft or Azure accounts allows users to log in with either a dedicated password or the credentials from their online account. Even after changing the account password, the old password remains valid for RDP logins indefinitely, and in some cases, multiple previous passwords may still grant access. This behavior poses significant security risks, especially if the account has been compromised, as changing the password does not block access via RDP with the old password. The issue arises from credential caching on the local machine, where the initial login credentials are stored securely, allowing continued access without online verification.