Overview

In mid-May 2025, the Indian Computer Emergency Response Team (CERT-In) issued an urgent advisory warning Windows users across India about critical vulnerabilities that could be exploited by cyber attackers. This alert underscores the necessity for immediate action to protect systems from potential threats.

Background

CERT-In's advisory highlights several vulnerabilities identified in Microsoft's April 2025 Patch Tuesday release. Notably, these include:

  • CVE-2025-29824: A use-after-free vulnerability in the Windows Common Log File System (CLFS) driver, allowing attackers to elevate privileges to SYSTEM level. This flaw has been actively exploited in the wild. (helpnetsecurity.com)
  • CVE-2025-26663 and CVE-2025-26670: Remote code execution vulnerabilities in the Windows Lightweight Directory Access Protocol (LDAP), which could enable unauthenticated attackers to execute arbitrary code on affected systems. (crowdstrike.com)
  • CVE-2025-27480 and CVE-2025-27482: Remote code execution vulnerabilities in Windows Remote Desktop Services (RDP), potentially allowing attackers to execute code without user interaction. (crowdstrike.com)

Technical Details

CVE-2025-29824: Windows CLFS Driver Elevation of Privilege Vulnerability

This vulnerability arises from a use-after-free condition in the CLFS driver, which can be exploited to gain SYSTEM privileges. Attackers have been observed leveraging this flaw in ransomware attacks. (helpnetsecurity.com)

CVE-2025-26663 and CVE-2025-26670: LDAP Remote Code Execution Vulnerabilities

These vulnerabilities involve race conditions in the LDAP service, allowing remote attackers to execute code by sending specially crafted requests. Exploitation requires winning a race condition but does not necessitate user interaction, increasing the risk of widespread attacks. (crowdstrike.com)

CVE-2025-27480 and CVE-2025-27482: RDP Remote Code Execution Vulnerabilities

These flaws exist in the Remote Desktop Gateway service and can be exploited by unauthenticated attackers to execute code remotely. Successful exploitation requires triggering a race condition, but no user interaction is needed, making these vulnerabilities particularly concerning. (crowdstrike.com)

Implications and Impact

The exploitation of these vulnerabilities can lead to:

  • Unauthorized access to sensitive data
  • Deployment of ransomware
  • Disruption of critical services
  • Potential for widespread attacks due to the lack of user interaction required for exploitation

Given the active exploitation of these vulnerabilities, it is imperative for organizations and individuals to take immediate action to secure their systems.

Recommended Actions

  1. Apply Security Updates: Ensure that all Windows systems are updated with the latest patches released by Microsoft in April 2025. (helpnetsecurity.com)
  2. Restrict Access to Services: Limit access to RDP and LDAP services to trusted sources only. Implement network-level authentication and consider using VPNs for remote access.
  3. Monitor Systems: Utilize Endpoint Detection and Response (EDR) tools to monitor for unusual activities, especially those related to the CLFS driver and LDAP services.
  4. Educate Users: Train staff to recognize phishing attempts and other social engineering tactics that could be used to exploit these vulnerabilities.
  5. Implement Network Segmentation: Divide networks into segments to limit the spread of potential attacks.

Conclusion

The vulnerabilities highlighted by CERT-In pose significant risks to Windows users in India. Prompt application of security patches, coupled with proactive security measures, is essential to mitigate these threats. Organizations should remain vigilant and adhere to best practices to safeguard their systems against potential cyberattacks.