Furthermore, the RPC runtime does not verify the legitimacy of RPC servers, and processes are allowed to deploy RPC servers exposing the same endpoints as legitimate services.To exploit PhantomRPC, Kabibo says, an attacker needs to compromise a privileged service, deploy a fake RPC server, listen to specific requests, and then impersonate the targeted service to escalate their privileges.Network Service account service abuseThe attacker could compromise a service running under the Network Service account and deploy a fake RPC server with the RPC interface UUID and exposed endpoint name as TermService, the default Remote Desktop service.The attacker could then force a policy update to cause the Group Policy service, which runs with System privileges, to perform an RPC call to TermService. Because TermService is disabled by default, the request would fail.However, the attacker’s RPC server, which also receives the RPC request, can now impersonate the security context of the Group Policy service and elevate privileges to System.After identifying other RPC clients attempting to communicate with unavailable servers, Kabibo discovered four other PhantomRPC exploitation paths, noting that the weakness leads to a large attack surface, because numerous system DLLs in Windows rely on RPC.“Applications that invoke seemingly benign APIs may unintentionally trigger privileged RPC interactions. Under certain conditions, these interactions could be abused to achieve local privilege escalation without the user’s knowledge,” the researcher says.In another scenario, the attacker’s fake RPC server would wait for a high-privileged user to launch Microsoft Edge, which makes an RPC call to the TermService upon start. The attacker’s server intercepts the request and elevates its privileges from Network Service to System.Another attack path listens to the background RPC calls that the Diagnostic System Host Service (WDI) periodically makes to TermService using a high impersonation level. Using the same setup, the attacker elevates privileges without user interaction, as the WDI automatically makes the calls every 5 to 15 minutes.Local Service account service abuseThe security researcher also discovered two attack paths that abuse a Local Service account to escalate privileges, such as the DHCP Client service, which is enabled by default and exposes an RPC server with multiple interfaces and endpoints.The attacker’s fake RPC server mimics the legitimate RPC service exposed by the DHCP Client and listens for the RPC calls that ipconfig makes to it when run by an administrator. The scenario assumes that the DHCP Client service is disabled, allowing the fake server to impersonate the client.The Windows Time service, also enabled by default under the Local Service account, exposes an RPC server with two endpoints, and the executable w32tm.exe interacts with it using RPC.Because w32tm.exe calls a nonexistent named pipe not exposed by the legitimate service, the attacker can deploy an RPC server that exposes it, then wait for a high-privileged user to run the executable so that the RPC request is redirected to the malicious server.“In this scenario, it is important to note that the legitimate Windows Time service does not need to be disabled. Because the executable attempts to connect to a nonexistent endpoint, it is sufficient for the attacker to expose that endpoint through the malicious RPC server,” the researcher says.Kaspersky reported the issue in September 2025. Microsoft classified it as moderate-severity due to the required impersonation privilege and said it does not require immediate remediation.SecurityWeekhas emailed Microsoft for a statement and will update this article if the company responds.Related:Incomplete Windows Patch Opens Door to Zero-Click AttacksRelated:Organizations Warned of Exploited Windows, Adobe Acrobat VulnerabilitiesRelated:In Other News: Cyberattack Stings Stryker, Windows Zero-Day, China Supercomputer HackRelated:ClickFix Attack Uses Windows Terminal to Evade Detection
To exploit PhantomRPC, Kabibo says, an attacker needs to compromise a privileged service, deploy a fake RPC server, listen to specific requests, and then impersonate the targeted service to escalate their privileges.Network Service account service abuseThe attacker could compromise a service running under the Network Service account and deploy a fake RPC server with the RPC interface UUID and exposed endpoint name as TermService, the default Remote Desktop service.The attacker could then force a policy update to cause the Group Policy service, which runs with System privileges, to perform an RPC call to TermService. Because TermService is disabled by default, the request would fail.However, the attacker’s RPC server, which also receives the RPC request, can now impersonate the security context of the Group Policy service and elevate privileges to System.After identifying other RPC clients attempting to communicate with unavailable servers, Kabibo discovered four other PhantomRPC exploitation paths, noting that the weakness leads to a large attack surface, because numerous system DLLs in Windows rely on RPC.“Applications that invoke seemingly benign APIs may unintentionally trigger privileged RPC interactions. Under certain conditions, these interactions could be abused to achieve local privilege escalation without the user’s knowledge,” the researcher says.In another scenario, the attacker’s fake RPC server would wait for a high-privileged user to launch Microsoft Edge, which makes an RPC call to the TermService upon start. The attacker’s server intercepts the request and elevates its privileges from Network Service to System.Another attack path listens to the background RPC calls that the Diagnostic System Host Service (WDI) periodically makes to TermService using a high impersonation level. Using the same setup, the attacker elevates privileges without user interaction, as the WDI automatically makes the calls every 5 to 15 minutes.Local Service account service abuseThe security researcher also discovered two attack paths that abuse a Local Service account to escalate privileges, such as the DHCP Client service, which is enabled by default and exposes an RPC server with multiple interfaces and endpoints.The attacker’s fake RPC server mimics the legitimate RPC service exposed by the DHCP Client and listens for the RPC calls that ipconfig makes to it when run by an administrator. The scenario assumes that the DHCP Client service is disabled, allowing the fake server to impersonate the client.The Windows Time service, also enabled by default under the Local Service account, exposes an RPC server with two endpoints, and the executable w32tm.exe interacts with it using RPC.Because w32tm.exe calls a nonexistent named pipe not exposed by the legitimate service, the attacker can deploy an RPC server that exposes it, then wait for a high-privileged user to run the executable so that the RPC request is redirected to the malicious server.“In this scenario, it is important to note that the legitimate Windows Time service does not need to be disabled. Because the executable attempts to connect to a nonexistent endpoint, it is sufficient for the attacker to expose that endpoint through the malicious RPC server,” the researcher says.Kaspersky reported the issue in September 2025. Microsoft classified it as moderate-severity due to the required impersonation privilege and said it does not require immediate remediation.SecurityWeekhas emailed Microsoft for a statement and will update this article if the company responds.Related:Incomplete Windows Patch Opens Door to Zero-Click AttacksRelated:Organizations Warned of Exploited Windows, Adobe Acrobat VulnerabilitiesRelated:In Other News: Cyberattack Stings Stryker, Windows Zero-Day, China Supercomputer HackRelated:ClickFix Attack Uses Windows Terminal to Evade Detection
The attacker could compromise a service running under the Network Service account and deploy a fake RPC server with the RPC interface UUID and exposed endpoint name as TermService, the default Remote Desktop service.The attacker could then force a policy update to cause the Group Policy service, which runs with System privileges, to perform an RPC call to TermService. Because TermService is disabled by default, the request would fail.However, the attacker’s RPC server, which also receives the RPC request, can now impersonate the security context of the Group Policy service and elevate privileges to System.After identifying other RPC clients attempting to communicate with unavailable servers, Kabibo discovered four other PhantomRPC exploitation paths, noting that the weakness leads to a large attack surface, because numerous system DLLs in Windows rely on RPC.“Applications that invoke seemingly benign APIs may unintentionally trigger privileged RPC interactions. Under certain conditions, these interactions could be abused to achieve local privilege escalation without the user’s knowledge,” the researcher says.In another scenario, the attacker’s fake RPC server would wait for a high-privileged user to launch Microsoft Edge, which makes an RPC call to the TermService upon start. The attacker’s server intercepts the request and elevates its privileges from Network Service to System.Another attack path listens to the background RPC calls that the Diagnostic System Host Service (WDI) periodically makes to TermService using a high impersonation level. Using the same setup, the attacker elevates privileges without user interaction, as the WDI automatically makes the calls every 5 to 15 minutes.Local Service account service abuseThe security researcher also discovered two attack paths that abuse a Local Service account to escalate privileges, such as the DHCP Client service, which is enabled by default and exposes an RPC server with multiple interfaces and endpoints.The attacker’s fake RPC server mimics the legitimate RPC service exposed by the DHCP Client and listens for the RPC calls that ipconfig makes to it when run by an administrator. The scenario assumes that the DHCP Client service is disabled, allowing the fake server to impersonate the client.The Windows Time service, also enabled by default under the Local Service account, exposes an RPC server with two endpoints, and the executable w32tm.exe interacts with it using RPC.Because w32tm.exe calls a nonexistent named pipe not exposed by the legitimate service, the attacker can deploy an RPC server that exposes it, then wait for a high-privileged user to run the executable so that the RPC request is redirected to the malicious server.“In this scenario, it is important to note that the legitimate Windows Time service does not need to be disabled. Because the executable attempts to connect to a nonexistent endpoint, it is sufficient for the attacker to expose that endpoint through the malicious RPC server,” the researcher says.Kaspersky reported the issue in September 2025. Microsoft classified it as moderate-severity due to the required impersonation privilege and said it does not require immediate remediation.SecurityWeekhas emailed Microsoft for a statement and will update this article if the company responds.Related:Incomplete Windows Patch Opens Door to Zero-Click AttacksRelated:Organizations Warned of Exploited Windows, Adobe Acrobat VulnerabilitiesRelated:In Other News: Cyberattack Stings Stryker, Windows Zero-Day, China Supercomputer HackRelated:ClickFix Attack Uses Windows Terminal to Evade Detection
The attacker could then force a policy update to cause the Group Policy service, which runs with System privileges, to perform an RPC call to TermService. Because TermService is disabled by default, the request would fail.However, the attacker’s RPC server, which also receives the RPC request, can now impersonate the security context of the Group Policy service and elevate privileges to System.After identifying other RPC clients attempting to communicate with unavailable servers, Kabibo discovered four other PhantomRPC exploitation paths, noting that the weakness leads to a large attack surface, because numerous system DLLs in Windows rely on RPC.“Applications that invoke seemingly benign APIs may unintentionally trigger privileged RPC interactions. Under certain conditions, these interactions could be abused to achieve local privilege escalation without the user’s knowledge,” the researcher says.In another scenario, the attacker’s fake RPC server would wait for a high-privileged user to launch Microsoft Edge, which makes an RPC call to the TermService upon start. The attacker’s server intercepts the request and elevates its privileges from Network Service to System.Another attack path listens to the background RPC calls that the Diagnostic System Host Service (WDI) periodically makes to TermService using a high impersonation level. Using the same setup, the attacker elevates privileges without user interaction, as the WDI automatically makes the calls every 5 to 15 minutes.Local Service account service abuseThe security researcher also discovered two attack paths that abuse a Local Service account to escalate privileges, such as the DHCP Client service, which is enabled by default and exposes an RPC server with multiple interfaces and endpoints.The attacker’s fake RPC server mimics the legitimate RPC service exposed by the DHCP Client and listens for the RPC calls that ipconfig makes to it when run by an administrator. The scenario assumes that the DHCP Client service is disabled, allowing the fake server to impersonate the client.The Windows Time service, also enabled by default under the Local Service account, exposes an RPC server with two endpoints, and the executable w32tm.exe interacts with it using RPC.Because w32tm.exe calls a nonexistent named pipe not exposed by the legitimate service, the attacker can deploy an RPC server that exposes it, then wait for a high-privileged user to run the executable so that the RPC request is redirected to the malicious server.“In this scenario, it is important to note that the legitimate Windows Time service does not need to be disabled. Because the executable attempts to connect to a nonexistent endpoint, it is sufficient for the attacker to expose that endpoint through the malicious RPC server,” the researcher says.Kaspersky reported the issue in September 2025. Microsoft classified it as moderate-severity due to the required impersonation privilege and said it does not require immediate remediation.SecurityWeekhas emailed Microsoft for a statement and will update this article if the company responds.Related:Incomplete Windows Patch Opens Door to Zero-Click AttacksRelated:Organizations Warned of Exploited Windows, Adobe Acrobat VulnerabilitiesRelated:In Other News: Cyberattack Stings Stryker, Windows Zero-Day, China Supercomputer HackRelated:ClickFix Attack Uses Windows Terminal to Evade Detection
However, the attacker’s RPC server, which also receives the RPC request, can now impersonate the security context of the Group Policy service and elevate privileges to System.After identifying other RPC clients attempting to communicate with unavailable servers, Kabibo discovered four other PhantomRPC exploitation paths, noting that the weakness leads to a large attack surface, because numerous system DLLs in Windows rely on RPC.“Applications that invoke seemingly benign APIs may unintentionally trigger privileged RPC interactions. Under certain conditions, these interactions could be abused to achieve local privilege escalation without the user’s knowledge,” the researcher says.In another scenario, the attacker’s fake RPC server would wait for a high-privileged user to launch Microsoft Edge, which makes an RPC call to the TermService upon start. The attacker’s server intercepts the request and elevates its privileges from Network Service to System.Another attack path listens to the background RPC calls that the Diagnostic System Host Service (WDI) periodically makes to TermService using a high impersonation level. Using the same setup, the attacker elevates privileges without user interaction, as the WDI automatically makes the calls every 5 to 15 minutes.Local Service account service abuseThe security researcher also discovered two attack paths that abuse a Local Service account to escalate privileges, such as the DHCP Client service, which is enabled by default and exposes an RPC server with multiple interfaces and endpoints.The attacker’s fake RPC server mimics the legitimate RPC service exposed by the DHCP Client and listens for the RPC calls that ipconfig makes to it when run by an administrator. The scenario assumes that the DHCP Client service is disabled, allowing the fake server to impersonate the client.The Windows Time service, also enabled by default under the Local Service account, exposes an RPC server with two endpoints, and the executable w32tm.exe interacts with it using RPC.Because w32tm.exe calls a nonexistent named pipe not exposed by the legitimate service, the attacker can deploy an RPC server that exposes it, then wait for a high-privileged user to run the executable so that the RPC request is redirected to the malicious server.“In this scenario, it is important to note that the legitimate Windows Time service does not need to be disabled. Because the executable attempts to connect to a nonexistent endpoint, it is sufficient for the attacker to expose that endpoint through the malicious RPC server,” the researcher says.Kaspersky reported the issue in September 2025. Microsoft classified it as moderate-severity due to the required impersonation privilege and said it does not require immediate remediation.SecurityWeekhas emailed Microsoft for a statement and will update this article if the company responds.Related:Incomplete Windows Patch Opens Door to Zero-Click AttacksRelated:Organizations Warned of Exploited Windows, Adobe Acrobat VulnerabilitiesRelated:In Other News: Cyberattack Stings Stryker, Windows Zero-Day, China Supercomputer HackRelated:ClickFix Attack Uses Windows Terminal to Evade Detection
After identifying other RPC clients attempting to communicate with unavailable servers, Kabibo discovered four other PhantomRPC exploitation paths, noting that the weakness leads to a large attack surface, because numerous system DLLs in Windows rely on RPC.“Applications that invoke seemingly benign APIs may unintentionally trigger privileged RPC interactions. Under certain conditions, these interactions could be abused to achieve local privilege escalation without the user’s knowledge,” the researcher says.In another scenario, the attacker’s fake RPC server would wait for a high-privileged user to launch Microsoft Edge, which makes an RPC call to the TermService upon start. The attacker’s server intercepts the request and elevates its privileges from Network Service to System.Another attack path listens to the background RPC calls that the Diagnostic System Host Service (WDI) periodically makes to TermService using a high impersonation level. Using the same setup, the attacker elevates privileges without user interaction, as the WDI automatically makes the calls every 5 to 15 minutes.Local Service account service abuseThe security researcher also discovered two attack paths that abuse a Local Service account to escalate privileges, such as the DHCP Client service, which is enabled by default and exposes an RPC server with multiple interfaces and endpoints.The attacker’s fake RPC server mimics the legitimate RPC service exposed by the DHCP Client and listens for the RPC calls that ipconfig makes to it when run by an administrator. The scenario assumes that the DHCP Client service is disabled, allowing the fake server to impersonate the client.The Windows Time service, also enabled by default under the Local Service account, exposes an RPC server with two endpoints, and the executable w32tm.exe interacts with it using RPC.Because w32tm.exe calls a nonexistent named pipe not exposed by the legitimate service, the attacker can deploy an RPC server that exposes it, then wait for a high-privileged user to run the executable so that the RPC request is redirected to the malicious server.“In this scenario, it is important to note that the legitimate Windows Time service does not need to be disabled. Because the executable attempts to connect to a nonexistent endpoint, it is sufficient for the attacker to expose that endpoint through the malicious RPC server,” the researcher says.Kaspersky reported the issue in September 2025. Microsoft classified it as moderate-severity due to the required impersonation privilege and said it does not require immediate remediation.SecurityWeekhas emailed Microsoft for a statement and will update this article if the company responds.Related:Incomplete Windows Patch Opens Door to Zero-Click AttacksRelated:Organizations Warned of Exploited Windows, Adobe Acrobat VulnerabilitiesRelated:In Other News: Cyberattack Stings Stryker, Windows Zero-Day, China Supercomputer HackRelated:ClickFix Attack Uses Windows Terminal to Evade Detection
“Applications that invoke seemingly benign APIs may unintentionally trigger privileged RPC interactions. Under certain conditions, these interactions could be abused to achieve local privilege escalation without the user’s knowledge,” the researcher says.In another scenario, the attacker’s fake RPC server would wait for a high-privileged user to launch Microsoft Edge, which makes an RPC call to the TermService upon start. The attacker’s server intercepts the request and elevates its privileges from Network Service to System.Another attack path listens to the background RPC calls that the Diagnostic System Host Service (WDI) periodically makes to TermService using a high impersonation level. Using the same setup, the attacker elevates privileges without user interaction, as the WDI automatically makes the calls every 5 to 15 minutes.Local Service account service abuseThe security researcher also discovered two attack paths that abuse a Local Service account to escalate privileges, such as the DHCP Client service, which is enabled by default and exposes an RPC server with multiple interfaces and endpoints.The attacker’s fake RPC server mimics the legitimate RPC service exposed by the DHCP Client and listens for the RPC calls that ipconfig makes to it when run by an administrator. The scenario assumes that the DHCP Client service is disabled, allowing the fake server to impersonate the client.The Windows Time service, also enabled by default under the Local Service account, exposes an RPC server with two endpoints, and the executable w32tm.exe interacts with it using RPC.Because w32tm.exe calls a nonexistent named pipe not exposed by the legitimate service, the attacker can deploy an RPC server that exposes it, then wait for a high-privileged user to run the executable so that the RPC request is redirected to the malicious server.“In this scenario, it is important to note that the legitimate Windows Time service does not need to be disabled. Because the executable attempts to connect to a nonexistent endpoint, it is sufficient for the attacker to expose that endpoint through the malicious RPC server,” the researcher says.Kaspersky reported the issue in September 2025. Microsoft classified it as moderate-severity due to the required impersonation privilege and said it does not require immediate remediation.SecurityWeekhas emailed Microsoft for a statement and will update this article if the company responds.Related:Incomplete Windows Patch Opens Door to Zero-Click AttacksRelated:Organizations Warned of Exploited Windows, Adobe Acrobat VulnerabilitiesRelated:In Other News: Cyberattack Stings Stryker, Windows Zero-Day, China Supercomputer HackRelated:ClickFix Attack Uses Windows Terminal to Evade Detection
In another scenario, the attacker’s fake RPC server would wait for a high-privileged user to launch Microsoft Edge, which makes an RPC call to the TermService upon start. The attacker’s server intercepts the request and elevates its privileges from Network Service to System.Another attack path listens to the background RPC calls that the Diagnostic System Host Service (WDI) periodically makes to TermService using a high impersonation level. Using the same setup, the attacker elevates privileges without user interaction, as the WDI automatically makes the calls every 5 to 15 minutes.Local Service account service abuseThe security researcher also discovered two attack paths that abuse a Local Service account to escalate privileges, such as the DHCP Client service, which is enabled by default and exposes an RPC server with multiple interfaces and endpoints.The attacker’s fake RPC server mimics the legitimate RPC service exposed by the DHCP Client and listens for the RPC calls that ipconfig makes to it when run by an administrator. The scenario assumes that the DHCP Client service is disabled, allowing the fake server to impersonate the client.The Windows Time service, also enabled by default under the Local Service account, exposes an RPC server with two endpoints, and the executable w32tm.exe interacts with it using RPC.Because w32tm.exe calls a nonexistent named pipe not exposed by the legitimate service, the attacker can deploy an RPC server that exposes it, then wait for a high-privileged user to run the executable so that the RPC request is redirected to the malicious server.“In this scenario, it is important to note that the legitimate Windows Time service does not need to be disabled. Because the executable attempts to connect to a nonexistent endpoint, it is sufficient for the attacker to expose that endpoint through the malicious RPC server,” the researcher says.Kaspersky reported the issue in September 2025. Microsoft classified it as moderate-severity due to the required impersonation privilege and said it does not require immediate remediation.SecurityWeekhas emailed Microsoft for a statement and will update this article if the company responds.Related:Incomplete Windows Patch Opens Door to Zero-Click AttacksRelated:Organizations Warned of Exploited Windows, Adobe Acrobat VulnerabilitiesRelated:In Other News: Cyberattack Stings Stryker, Windows Zero-Day, China Supercomputer HackRelated:ClickFix Attack Uses Windows Terminal to Evade Detection
Another attack path listens to the background RPC calls that the Diagnostic System Host Service (WDI) periodically makes to TermService using a high impersonation level. Using the same setup, the attacker elevates privileges without user interaction, as the WDI automatically makes the calls every 5 to 15 minutes.Local Service account service abuseThe security researcher also discovered two attack paths that abuse a Local Service account to escalate privileges, such as the DHCP Client service, which is enabled by default and exposes an RPC server with multiple interfaces and endpoints.The attacker’s fake RPC server mimics the legitimate RPC service exposed by the DHCP Client and listens for the RPC calls that ipconfig makes to it when run by an administrator. The scenario assumes that the DHCP Client service is disabled, allowing the fake server to impersonate the client.The Windows Time service, also enabled by default under the Local Service account, exposes an RPC server with two endpoints, and the executable w32tm.exe interacts with it using RPC.Because w32tm.exe calls a nonexistent named pipe not exposed by the legitimate service, the attacker can deploy an RPC server that exposes it, then wait for a high-privileged user to run the executable so that the RPC request is redirected to the malicious server.“In this scenario, it is important to note that the legitimate Windows Time service does not need to be disabled. Because the executable attempts to connect to a nonexistent endpoint, it is sufficient for the attacker to expose that endpoint through the malicious RPC server,” the researcher says.Kaspersky reported the issue in September 2025. Microsoft classified it as moderate-severity due to the required impersonation privilege and said it does not require immediate remediation.SecurityWeekhas emailed Microsoft for a statement and will update this article if the company responds.Related:Incomplete Windows Patch Opens Door to Zero-Click AttacksRelated:Organizations Warned of Exploited Windows, Adobe Acrobat VulnerabilitiesRelated:In Other News: Cyberattack Stings Stryker, Windows Zero-Day, China Supercomputer HackRelated:ClickFix Attack Uses Windows Terminal to Evade Detection
The security researcher also discovered two attack paths that abuse a Local Service account to escalate privileges, such as the DHCP Client service, which is enabled by default and exposes an RPC server with multiple interfaces and endpoints.The attacker’s fake RPC server mimics the legitimate RPC service exposed by the DHCP Client and listens for the RPC calls that ipconfig makes to it when run by an administrator. The scenario assumes that the DHCP Client service is disabled, allowing the fake server to impersonate the client.The Windows Time service, also enabled by default under the Local Service account, exposes an RPC server with two endpoints, and the executable w32tm.exe interacts with it using RPC.Because w32tm.exe calls a nonexistent named pipe not exposed by the legitimate service, the attacker can deploy an RPC server that exposes it, then wait for a high-privileged user to run the executable so that the RPC request is redirected to the malicious server.“In this scenario, it is important to note that the legitimate Windows Time service does not need to be disabled. Because the executable attempts to connect to a nonexistent endpoint, it is sufficient for the attacker to expose that endpoint through the malicious RPC server,” the researcher says.Kaspersky reported the issue in September 2025. Microsoft classified it as moderate-severity due to the required impersonation privilege and said it does not require immediate remediation.SecurityWeekhas emailed Microsoft for a statement and will update this article if the company responds.Related:Incomplete Windows Patch Opens Door to Zero-Click AttacksRelated:Organizations Warned of Exploited Windows, Adobe Acrobat VulnerabilitiesRelated:In Other News: Cyberattack Stings Stryker, Windows Zero-Day, China Supercomputer HackRelated:ClickFix Attack Uses Windows Terminal to Evade Detection
Source: SecurityWeek
