Author: Ameeba

Overview

In the realm of cybersecurity, managing system privileges is a critical aspect of maintaining data security. Recently, a new vulnerability identified as CVE-2025-29976 has come to light, having a substantial impact on Microsoft Office SharePoint. This vulnerability allows an authorized user to elevate their privileges within the system, leading to potential data leakage or even full system compromise. Given the widespread usage of SharePoint across various organizations for managing and sharing documents, this vulnerability has serious implications.

Vulnerability Summary

CVE ID: CVE-2025-29976
Severity: High (CVSS:7.8)
Attack Vector: Local
Privileges Required: Low
User Interaction: Required
Impact: System compromise and potential data leakage

Affected Products

Product | Affected Versions

Microsoft Office SharePoint | All versions prior to the patched release

How the Exploit Works

This exploit takes advantage of the improper privilege management within Microsoft Office SharePoint. In essence, an authorized user with low-level privileges can exploit this vulnerability to gain higher-level access rights, which should ideally be restricted. This could be achieved through specific sequences of system requests or commands that manipulate the privilege escalation flaw. This unauthorized elevation of privilege could then be used to perform actions such as accessing sensitive data, modifying system settings, or even taking control of the system.

Conceptual Example Code

The following is a conceptual representation of how the vulnerability might be exploited. This is not an actual exploit code but a simplified illustration.

POST /elevatePrivilege HTTP/1.1
Host: vulnerableSharePoint.example.com
Content-Type: application/json
{
"user": "lowPrivilegeUser",
"action": "increasePrivilege",
"targetLevel": "admin"
}

In this example, the low privilege user ‘lowPrivilegeUser’ sends a request to elevate their privilege level to ‘admin. If the system is vulnerable (i.e., it has not patched against CVE-2025-29976), it would grant this request, leading to privilege escalation.

Mitigation Guidance

The most effective way to mitigate this vulnerability is to apply the vendor-supplied patch. Microsoft has already addressed this vulnerability in its latest SharePoint updates. Organizations are strongly recommended to update their SharePoint deployments to the patched version as soon as possible.
In cases where immediate patching is not feasible, temporary mitigation can be achieved through the use of a Web Application Firewall (WAF) or Intrusion Detection Systems (IDS). These tools can help monitor and block suspicious activities that might indicate an attempt to exploit this vulnerability. However, these are temporary measures and should not replace the necessary system update.

Overview

This blog post seeks to provide a detailed analysis of the Common Vulnerabilities and Exposures (CVE) entry, CVE-2025-29975. This vulnerability affects the Microsoft PC Manager software and exposes systems to risks of unauthorized privilege escalation by an attacker. The impact of this vulnerability is crucial as it could lead to system compromise or data leakage, thereby endangering the confidentiality, integrity, and availability of the systems.

Vulnerability Summary

CVE ID: CVE-2025-29975
Severity: High (7.8 CVSS Score)
Attack Vector: Local
Privileges Required: Low
User Interaction: Required
Impact: Unauthorised Privilege Escalation leading to potential system compromise or data leakage

Affected Products

Product | Affected Versions

Microsoft PC Manager | All versions before the vendor patch

How the Exploit Works

The vulnerability stems from a flaw in the Microsoft PC Manager’s file access operation, specifically, the improper resolution of links before file access, also known as ‘link following. This flaw allows an attacker, who already has low-level privileges, to manipulate the link resolution process to access files or execute commands. This could result in an elevation of the attacker’s privileges, giving them unauthorized access to system resources or data.

Conceptual Example Code

To demonstrate how this vulnerability might be exploited, let us consider a hypothetical scenario where an attacker has gained low-level access to a system. They could use the following shell command to manipulate the link following process:

# Attacker creates a symbolic link to a sensitive file
ln -s /etc/sensitive_file /tmp/vulnerable_link
# Attacker manipulates Microsoft PC Manager's link resolution process to access the sensitive file
./MicrosoftPCManager --access-file=/tmp/vulnerable_link

In this example, the attacker creates a symbolic link pointing to a sensitive file. The attacker then manipulates the Microsoft PC Manager’s link resolution process to follow this symbolic link and access the content of the sensitive file.
The vulnerability can be mitigated by applying the vendor-provided patch. In the absence of a patch, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can serve as temporary mitigation by identifying and blocking malicious activities. However, these are not long-term solutions and systems should be patched as soon as possible to ensure security.

Overview

The cybersecurity community is recent witness to a critical vulnerability in the Microsoft Brokering File System, known as CVE-2025-29970. This vulnerability, if exploited, allows an authorized attacker to escalate their privileges locally, potentially leading to system compromise or data leakage. Given the widespread usage of Microsoft systems across corporate, institutional, and individual platforms, this vulnerability has the potential to affect a large number of users, making its mitigation and resolution an imperative task.

Vulnerability Summary

CVE ID: CVE-2025-29970
Severity: High (7.8 CVSS Score)
Attack Vector: Local
Privileges Required: Low
User Interaction: None
Impact: System compromise or data leakage

Affected Products

Product | Affected Versions

Microsoft Brokering File System | All versions prior to the patch

How the Exploit Works

The vulnerability lies in the “use after free” flaw in the Microsoft Brokering File System. In essence, a “use after free” vulnerability occurs when a program continues to use a pointer after it has been freed. This can lead to program crashes and potentially allow an attacker to execute arbitrary code.
In the case of CVE-2025-29970, an attacker with local access can exploit this flaw to escalate their privileges. The exploit manipulates memory management, tricking the system into executing unauthorized commands with elevated privileges.

Conceptual Example Code

The following conceptual example demonstrates how an attacker might exploit this vulnerability:

#include <stdio.h>
#include <stdlib.h>
int main() {
char *ptr = malloc(10); // allocate memory
free(ptr); // free the memory
// "use after free" vulnerability
sprintf(ptr, "command with elevated privileges");
system(ptr); // execute the command
}

In this example, memory is allocated to the `ptr` pointer, then freed, and then used again to execute a command with elevated privileges.

Mitigation Guidance

To mitigate this vulnerability, it is advised that users apply the vendor patch as soon as it becomes available. In the meantime, users can employ a Web Application Firewall (WAF) or Intrusion Detection System (IDS) as temporary mitigation. Regular monitoring for any suspicious activity and maintaining up-to-date security measures are also recommended to protect against such vulnerabilities.