The research describes PhantomRPC as an architectural weakness in Microsoft RPC (MSRPC), the communication system Windows uses to let one process invoke functions in another. Because RPC is deeply integrated into Windows interprocess communication and widely used by services and applications, weaknesses in this area can create multiple paths to escalation.

What PhantomRPC is

PhantomRPC is presented as a new vulnerability in the RPC architecture that enables a novel local privilege escalation technique. The core idea is that an attacker can create a fake RPC server and use that setup to gain higher privileges. The researcher notes that this differs fundamentally from the well-known “Potato” exploit family.

The research emphasizes that the issue is not limited to one specific application or service. Instead, it stems from how RPC works at an architectural level. As a result, the number of potential attack vectors is described as effectively unlimited, since any new process or service that depends on RPC could introduce another escalation path.

How Windows RPC fits into the problem

Microsoft RPC follows a client-server model. One process exposes functionality through an RPC interface, and another process can call functions on that interface across different execution contexts. Each interface is identified by a UUID, which helps the operating system distinguish one RPC interface from another.

In the context of PhantomRPC, this structure matters because services that rely on RPC may be coerced or manipulated into interacting with a fake server. The research says that processes with impersonation privileges can use this technique to escalate permissions to SYSTEM level.

Exploitation paths described in the research

Kabibo says the issue can be used through several different paths. The research outlines five exploitation paths showing privilege escalation from various local or network service contexts to SYSTEM or other high-privileged users. Some of these paths rely on coercion, some require user interaction, and others make use of background services.

The article’s table of contents highlights several example scenarios examined in the research, including:

• User interaction, such as moving from Edge to RDP
• Background services, such as moving from WDI to RDP
• Abusing the Local Service account, such as moving from ipconfig to DHCP
• Abusing Time

The research also mentions interaction between the Group Policy service and TermService, and describes coercing the Group Policy service through the RPC architecture flow. These examples are presented as demonstrations of how different Windows components that depend on RPC may be abused for escalation.

Identifying and defending against attack opportunities

Because the weakness is architectural, the researcher says new services or processes that use RPC could create additional escalation opportunities in the future. For that reason, the research includes a methodology for identifying such opportunities.

The article also discusses detection and defensive approaches. While the source notes that possible detection strategies and mitigations are examined, it does not claim a confirmed root cause beyond the architectural weakness in RPC itself. The key takeaway is that the problem arises from the way RPC-based interactions can be manipulated to create a privileged fake server scenario.

Why the disclosure matters

PhantomRPC stands out because it is described as a broad local privilege escalation technique rather than a narrow bug in a single product component. The combination of impersonation privileges, RPC architecture, and service interactions creates multiple potential routes to SYSTEM-level access.

Kaspersky’s disclosure underscores how complex Windows IPC and RPC remain as security surfaces. The research suggests that the impact may extend across many Windows versions and many RPC-dependent processes, which makes timely analysis and mitigation especially important.

Conclusion

PhantomRPC highlights a serious privilege escalation risk in Windows RPC architecture. Kaspersky reports that the technique can let attackers create a fake RPC server and elevate privileges to SYSTEM in multiple scenarios. Microsoft has not yet released a patch, and the source presents the issue as an architectural weakness with potentially broad impact.