The cyber security landscape is grappling with a significant development—a fresh variant of DLL (Dynamic Link Library) Search Order hijacking that poses a formidable challenge to the security mechanisms of Windows 10 and 11. This novel technique, recently detailed by security researchers, introduces a unique twist by leveraging executable within the trusted WinSxS folder, offering threat actors an avenue to bypass security protocols and execute malicious code.

Technical Details:

This sophisticated approach capitalizes on the classic DLL search order hijacking technique, specifically targeting executable commonly found in the critical WinSxS folder. By doing so, adversaries can bypass the need for elevated privileges, enabling the execution of nefarious code on compromised machines. Additionally, this variant introduces the potential for incorporating vulnerable binaries into the attack chain.

• Vulnerability Type: DLL Search Order Hijacking
• Affected Systems: Windows 10 and 11
• Impact: Unauthorized code execution, potential system compromise
• Indicators of Compromise (IoCs):

1. Unexpected DLL file executions
2. Anomalies in system or application behaviour
3. Unusual registry modifications

• Detection Rules:

1. Monitoring for unexpected or unauthorized DLL file loads
2. Behavioural analysis for abnormal system activities
3. Signature-based detection for known variants

Main Content:

DLL Search Order Hijacking, a technique where attackers exploit the way applications search for DLL files, has taken an alarming turn with a new variant successfully evading Windows 10 and 11 protections. The sophistication of this exploit, coupled with the potential for executing unauthorized code, raises significant concerns. Its versatility allows cybercriminals to deploy this vulnerability in various scenarios, posing threats ranging from data breaches to complete system takeovers. Understanding and mitigating these risks becomes imperative for Windows users.

Understanding DLL Search Order Hijacking:

DLL search order hijacking involves manipulating the order in which Windows loads DLLs to execute malicious payloads, facilitating defences evasion, persistence, and privilege escalation. In this scenario, threat actors pinpoint applications that do not specify the full path to required DLLs, relying on a predefined search order to locate them on disk.

Exploiting this behaviour, attackers move legitimate system binaries into non-standard directories, housing malicious DLLs with names mirroring authentic ones. This strategic placement ensures that the DLL containing the attack code is loaded instead of the legitimate one. The search order encompasses directories such as the application launch directory, system folders, and those listed in the PATH environment variables.

Innovative Twist in Exploitation:

Security researchers, introduces a unique twist by focusing on files within the trusted “C:\Windows\WinSxS” folder. This critical Windows component, abbreviated as Windows side-by-side (WinSxS), is integral for OS customization and updates to ensure compatibility and integrity.

The exploitation method involves identifying vulnerable binaries in the WinSxS folder, combining them with traditional DLL search order hijacking methods. By strategically placing a custom DLL with the same name as a legitimate DLL in an actor-controlled directory, adversaries achieve code execution. Executing a vulnerable file in the WinSxS folder triggers the execution of the rogue DLL’s contents without copying the executable.

Remediation Steps:

• Regular System Updates: Ensure that both Windows and all installed applications are consistently updated with the latest security patches. This helps in fortifying defenses against evolving threats.
• Enhanced Monitoring: Implement advanced monitoring tools capable of detecting unusual DLL activities. Proactive monitoring is crucial to identifying potential security breaches in their early stages.
• Employee Education: Educate users about the risks associated with downloading and executing unknown files. Building a cyber security-aware workforce is an essential component of a robust defense strategy.
• Application Whitelisting: Employ application whitelisting to exert control over which DLL files can be executed. This ensures that only trusted and authorized files run on the system.
• System Hardening: Implement best practices in system configuration to minimize vulnerabilities. This includes securing configurations and settings to reduce the attack surface.
• Regular Security Audits: Conduct periodic security audits to identify and address potential security gaps. Regular assessments help in staying ahead of emerging threats and vulnerabilities.
• Incident Response Plan: Develop and maintain a robust incident response plan to ensure a swift and effective response to any security breaches. This includes predefined steps for investigation, containment, and recovery.

Conclusion:

As the cybersecurity landscape advances, staying informed and adopting proactive measures is crucial. The threat of DLL Search Order Hijacking exploiting Windows 10 and 11 requires a comprehensive and vigilant approach to safeguard systems against potential compromise.