Cybersecurity Researchers Uncover Windows EPM Exploit Chain Leading to Domain Privilege Escalation

What's Happening?

Cybersecurity researchers have identified a vulnerability in Microsoft's Windows Remote Procedure Call (RPC) communication protocol that could be exploited for domain privilege escalation. The flaw, known as CVE-2025-49760, was addressed in Microsoft's July 2025 Patch Tuesday update. SafeBreach researcher Ron Ben Yizhak presented the findings at the DEF CON 33 security conference, revealing how attackers could manipulate the Endpoint Mapper (EPM) to impersonate legitimate services. This exploit allows unauthorized users to register interfaces of core services, potentially leading to privilege escalation by coercing protected processes to authenticate against arbitrary servers.

Why It's Important?

The discovery of this vulnerability highlights significant security risks within Windows systems, particularly concerning the RPC protocol's Endpoint Mapper. The ability to impersonate core services and manipulate RPC clients poses a threat to enterprise security, potentially allowing attackers to escalate privileges and access sensitive data. Organizations relying on Windows systems must ensure they apply the latest patches to mitigate these risks. The exploit underscores the importance of robust security measures and monitoring tools to detect and prevent such attacks, which could lead to data breaches and compromise of critical infrastructure.

What's Next?

Organizations are advised to implement security measures that monitor calls to RpcEpRegister and utilize Event Tracing for Windows (ETW) to detect potential EPM poisoning attacks. SafeBreach has released a tool, RPC-Racer, to identify insecure RPC services and prevent unauthorized interface registration. As the cybersecurity community continues to explore the implications of this vulnerability, further research may uncover additional vulnerable interfaces and clients. Microsoft and other stakeholders may need to enhance the security design of the Endpoint Mapper to prevent future exploitation.

Beyond the Headlines

The vulnerability raises questions about the security architecture of Windows systems, particularly the lack of verification in the Endpoint Mapper's design. This oversight allows attackers to manipulate client actions, highlighting the need for improved security protocols that verify the identity of RPC servers. The incident may prompt broader discussions on the security of communication protocols and the importance of proactive vulnerability management in safeguarding digital infrastructure.