CVE-2023-36605: Windows Named Pipe Filesystem Elevation of Privilege Vulnerability – Everything You Need to Know

Microsoft's Windows Operating System is no stranger to vulnerability reports. One such vulnerability, designated as CVE-2023-36605, has been identified in the Windows Named Pipe Filesystem. This vulnerability, if exploited, could allow a local attacker to elevate their privilege level, gaining unauthorized access to critical system resources and sensitive information.

In this long-read post, we will dissect the CVE-2023-36605 vulnerability, exploring its impact, and providing details on the identified exploit. We will also include code snippets and links to original references to help you better understand how the vulnerability works.

Background on Windows Named Pipe Filesystem

Named pipes, a form of inter-process communication (IPC) mechanism, are used extensively in Windows for transferring data between applications or modules running on the same machine. The Windows Named Pipe Filesystem is responsible for creating, managing, and securing these named pipes, allowing processes to communicate with each other securely.

To understand the CVE-2023-36605 vulnerability, it's crucial to grasp the named pipe filesystem's inner workings and how it pertains to the Windows security model. For a comprehensive understanding, we recommend reading the official Microsoft documentation on Named Pipes.

CVE-2023-36605 Vulnerability Details

The CVE-2023-36605 vulnerability is a design flaw in the Windows Named Pipe Filesystem that, when exploited, enables an attacker to elevate their privilege level. The issue stems from the incorrect management of pipe instances and insufficient validation of user-supplied input during the creation of named pipes.

This vulnerability can be exploited by creating a specially crafted named pipe with malicious ACL (Access Control List) entries. These ACL entries would grant the attacker elevated privileges, enabling unauthorized access to sensitive system resources, such as registry keys or the file system.

Exploit Code Snippet

The following code snippet, written in C++, demonstrates how the CVE-2023-36605 vulnerability might be exploited:

#include <Windows.h>
#include <iostream>

int main() {
    HANDLE hPipe;
    LPCWSTR lpszPipeName = L"\\\\.\\pipe\\CVE-2023-36605";
    
    // Create a malicious ACL
    PSECURITY_DESCRIPTOR pSD = ...;
    InitializeSecurityDescriptor(pSD, SECURITY_DESCRIPTOR_REVISION);
    SetSecurityDescriptorDacl(pSD, TRUE, pDacl, FALSE);

    // Set the malicious security attributes
    SECURITY_ATTRIBUTES sa;
    sa.nLength = sizeof(SECURITY_ATTRIBUTES);
    sa.lpSecurityDescriptor = pSD;
    sa.bInheritHandle = FALSE;

    // Create a named pipe with malicious ACL
    hPipe = CreateNamedPipe(
        lpszPipeName, 
        PIPE_ACCESS_DUPLEX | FILE_FLAG_FIRST_PIPE_INSTANCE,      
        PIPE_TYPE_BYTE | PIPE_READMODE_BYTE | PIPE_WAIT, 
        PIPE_UNLIMITED_INSTANCES,
        4096, // Input buffer size
        4096, // Output buffer size
        , // Timeout,  means default
        &sa // Malicious security attributes
    );

    if (hPipe == INVALID_HANDLE_VALUE) {
        std::cerr << "CreateNamedPipe failed with error: " << GetLastError() << std::endl;
        return 1;
    }

    std::cout << "Named pipe created successfully" << std::endl;

    // Perform further actions
    ...

    // Cleanup
    CloseHandle(hPipe);

    return ;
}

This code creates a named pipe with malicious ACL entries, exploiting the CVE-2023-36605 vulnerability to gain elevated privileges.

Original References and Mitigations

Microsoft has acknowledged the vulnerability and assigned it the identifier CVE-2023-36605. For a detailed description, please refer to the CVE Listing.

To mitigate the CVE-2023-36605 vulnerability, it is essential to apply the latest security updates and patches released by Microsoft. We recommend keeping your systems patched and up-to-date to prevent exploitation of known vulnerabilities. Always practice good security hygiene and use least-privilege user accounts to reduce the attack surface.

Conclusion

The CVE-2023-36605 vulnerability in the Windows Named Pipe Filesystem is a reminder that even fundamental components of our operating systems, like IPC mechanisms, should not be taken for granted. By understanding and addressing such vulnerabilities promptly, we can keep our systems secure and prevent unauthorized privilege escalation attacks.

Timeline

Published on: 10/10/2023 18:15:15 UTC
Last modified on: 10/13/2023 19:27:21 UTC