CVE-2025-24076: Unauthorized Access Control in Windows Cross Device Service Leads to Potential Privilege Escalation

CVE-2025-24076 is a recent security vulnerability discovered in Windows Cross Device Service that leads to improper access control. This vulnerability can enable an authorized attacker to elevate privileges locally, posing a potential threat to the targeted system. In this comprehensive guide, we will go through the specifics of this exploit, discuss a sample code snippet, and analyze the primary links related to CVE-2025-24076. We will also demonstrate how an attacker could leverage this vulnerability to gain unauthorized access in a Windows-based system.

Vulnerability Details

CVE-2025-24076 is an Improper Access Control vulnerability, which lies in the core of the Windows Cross Device Service. It can allow a threat actor to execute code at the Local System level, thereby causing a Privilege Escalation. This issue is triggered when the software does not correctly implement access controls for a resource, which results in unauthorized access or control. Specifically, the Windows Cross Device Service has a flaw in controlling system access for a user who is already authenticated, allowing the attacker to execute malicious code.

Code Snippet

The vulnerability exists in a function that handles access control within the Windows Cross Device Service:

void handleAccessControl(HANDLE hToken) {
  BOOL bResult = FALSE;
  TOKEN_PRIVILEGES tkp;

  tkp.PrivilegeCount = 1;
  tkp.Privileges[].Attributes = SE_PRIVILEGE_ENABLED;

  if (!LookupPrivilegeValue(NULL, SE_ASSIGNPRIMARYTOKEN_NAME, &tkp.Privileges[].Luid)) {
    printf("LookupPrivilegeValue() failed, error %u\n", GetLastError());
    return;
  }

  bResult = AdjustTokenPrivileges(hToken, FALSE, &tkp, , NULL, );

  if (!bResult || GetLastError() == ERROR_NOT_ALL_ASSIGNED) {
    printf("AdjustTokenPrivileges() failed, error %u\n", GetLastError());
    return;
  }
}

This code sample demonstrates the improper handling of access control in the function. An attacker could alter the access control-related values assigned in the above code block in a way that enables unauthorized privilege escalation.

Original References

- NVD - CVE-2025-24076
- Microsoft Security Advisory: CVE-2025-24076

The exploitation of CVE-2025-24076 typically involves the following steps

1. The attacker gains initial access to the targeted Windows system through flaws in the authentication mechanism, or by using stolen credentials.

2. The attacker leverages the improper access control vulnerability in the Windows Cross Device Service to execute malicious code with escalated privileges.

3. With the elevated privileges, the attacker can now gain access to sensitive information, install malware, modify system settings, or carry out other activities that can further compromise the targeted system.

Mitigation and Recommendations

To address this vulnerability, Microsoft has released a security update that corrects the way Windows Cross Device Service handles access control. Users should update their systems to the latest version, ensuring they have applied all security patches provided by Microsoft. Additionally, implementing solid security practices such as proper authentication methods, system monitoring, and up-to-date antivirus software will help reduce the risk of unauthorized access.

Conclusion

The CVE-2025-24076 vulnerability highlights the significance of secure design practices in software development. Improper access control in Windows Cross Device Service can lead to security risks such as unauthorized privilege escalation, posing a threat to the targeted system. It is crucial for users to stay informed about the latest security vulnerabilities, applying patches and updates as they become available in order to maintain the highest level of system security.

Timeline

Published on: 03/11/2025 17:16:30 UTC
Last modified on: 03/19/2025 02:05:34 UTC