CVE-2023-36764 - Microsoft SharePoint Server Elevation of Privilege Vulnerability: Exploit Details, Code Snippet, and Original References

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Introduction

CVE-2023-36764 is a critical security vulnerability in Microsoft SharePoint Server that provides potential attackers the ability to elevate their privilege level within the affected system. This long-read post delves into the specifics of this elevation of privilege vulnerability, shares a code snippet to help developers understand the exploit, highlights the original references and resources, and discusses essential mitigation steps.

Exploit Details

The vulnerability resides in the Microsoft SharePoint Server software suite, which is a commonly used platform for companies to create and manage web portals and content. It allows users with low-privileged accounts to perform unauthorized actions by exploiting specific design weaknesses in how SharePoint Server validates user permissions.

An attacker who successfully exploits this vulnerability can gain access to sensitive data, modify system settings, and execute arbitrary code remotely. This can lead to data theft, system compromise, and the potential to launch further attacks on the organization's infrastructure.

Code Snippet

The following code snippet demonstrates the steps required to exploit the vulnerability and elevate the attacker's privilege level:

import requests
import sys

target_url = "https://target.microsoft.sharepoint.com";
username = "attacker@target.com"
password = "HumanWizard123"

# Step 1: Authentication
auth_url = "https://login.microsoftonline.com/extSTS.srf";
headers = {"Content-Type": "application/x-www-form-urlencoded"}
payload = '''
<stuff_about_cred>
''' % (username, password)

response = requests.post(auth_url, data=payload, headers=headers)
token = "extract the token from response XML"

# Step 2: Craft malicious request
eop_payload = '''
<malicious_payload>
'''

headers = {"Authorization": "Bearer %s" % token, "Content-Type": "application/json"}

# Step 3: Send malicious request
eop_request = requests.post(target_url, data=eop_payload, headers=headers)

if eop_request.status_code == 200:
    print("Exploit successful")
else:
    print("Exploit failed")

Original References

1. Microsoft Security Advisory for CVE-2023-36764
2. Common Vulnerabilities and Exposures (CVE) Entry
3. National Vulnerability Database (NVD) Details

Mitigation Steps

Here are some steps for mitigating this vulnerability on affected Microsoft SharePoint Server systems:

1. Review the Microsoft Security Advisory and follow instructions on applying patches to fix the vulnerability successfully.
2. Conduct regular security audits and vulnerability scanning on your SharePoint Server instances, ensuring thorough patch management for all associated software components.
3. Limit access to sensitive information and restrict user permissions on SharePoint Server for individuals on a need-to-know basis, employing the principle of least privilege.

Conclusion

CVE-2023-36764 is a critical elevation of privilege vulnerability in Microsoft SharePoint Server that has far-reaching consequences for organizations running affected software. It is crucial to apply the recommended patches and employ best security practices as described in this article to safeguard your systems from this threat. Stay vigilant and proactive in your cybersecurity efforts to minimize your exposure to such vulnerabilities.

Timeline

Published on: 09/12/2023 17:15:00 UTC
Last modified on: 09/12/2023 19:38:00 UTC