Author: Ameeba

Overview

The world of cybersecurity is an ever-evolving landscape, with new vulnerabilities being discovered regularly. Most recently, a critical vulnerability identified as CVE-2025-36631 has been identified in Tenable Agent versions prior to 10.8.5. This vulnerability allows non-administrative users to overwrite arbitrary local system files with log content at SYSTEM privilege on a Windows host. This vulnerability is significant as it can lead to potential system compromise or data leakage, putting sensitive data at risk.
In this blog post, we delve into the details of this vulnerability, its potential impacts, and the steps that system administrators and cybersecurity professionals can take to mitigate its effects. Understanding the nature of this vulnerability is critical, especially for organizations using affected versions of Tenable Agent.

Vulnerability Summary

CVE ID: CVE-2025-36631
Severity: Critical (8.4)
Attack Vector: Local
Privileges Required: None
User Interaction: Required
Impact: System compromise and potential data leakage

Affected Products

Product | Affected Versions

Tenable Agent | Versions prior to 10.8.5

How the Exploit Works

The vulnerability works by exploiting the Tenable Agent’s improper handling of file permissions. Specifically, an unprivileged user can manipulate the logging feature of the Tenable Agent to overwrite any local system files. This is done by redirecting the output of the log files to system files, effectively granting the attacker SYSTEM level privileges.
This vulnerability can be exploited by a local attacker who has access to the system and can log in as a non-administrative user. Once the attacker gains SYSTEM privileges, they can perform various malicious activities, including modifying system configurations, installing malicious software, or even exfiltrating sensitive data.

Conceptual Example Code

Below is a conceptual example of how this vulnerability might be exploited. It demonstrates how an attacker could use a simple command-line instruction to redirect the output of the Tenable Agent logs to overwrite a system file.

# Overwrite a system file with Tenable Agent log content
echo "C:\\Path\\To\\TenableAgentLogs" > "C:\\Windows\\System32\\targetfile.dll"

Please note: This is a simplified conceptual example and actual exploitation may require more complex steps or specific conditions. Always adhere to ethical guidelines when exploring such vulnerabilities in a controlled environment.

Overview

CVE-2025-47957 represents a significant vulnerability in Microsoft Office Word, a widely-used software application across organizations of all sizes globally. This vulnerability is categorized as a Use-After-Free flaw, which if exploited, permits an unauthorized attacker to execute code locally on the victim’s machine. Given the ubiquity of Microsoft Office Word, this vulnerability holds the potential to impact a vast number of systems, warranting immediate attention and mitigation from all users and administrators.

Vulnerability Summary

CVE ID: CVE-2025-47957
Severity: Critical (CVSS Severity Score: 8.4)
Attack Vector: Local
Privileges Required: Low
User Interaction: Required
Impact: System Compromise, Data Leakage

Affected Products

Product | Affected Versions

Microsoft Office Word | All versions prior to the vendor patch

How the Exploit Works

The exploit works by leveraging a Use-After-Free vulnerability present in Microsoft Office Word. This class of vulnerability arises when a program continues to use a pointer after it has been freed. An attacker can manipulate this flaw by crafting a malicious document that, when opened in Word, triggers the vulnerability and allows the attacker to execute code locally on the victim’s machine.

Conceptual Example Code

While the exact exploit code would be specific to the attacker, a conceptual example of how this vulnerability might be exploited could look like this:

#include <windows.h>
// The malicious payload
void payload() {
//...
}
// The function to trigger the use-after-free vulnerability
void trigger_vulnerability() {
char* ptr = (char*) malloc(100);
strcpy(ptr, "sensitive data");
free(ptr);
// Use after free
strcpy(ptr, payload);
}
int main() {
trigger_vulnerability();
return 0;
}

In this simplified conceptual example, the `trigger_vulnerability` function first allocates memory (`ptr`), then frees it, and finally attempts to use it again to store the malicious payload. This results in undefined behavior, which an attacker can potentially leverage to execute their malicious payload.

Mitigation and Remediation

The primary mitigation strategy for CVE-2025-47957 is to apply the vendor-provided patch. Microsoft has released a patch that resolves this vulnerability, and it is strongly recommended that all users and system administrators download and install this patch as soon as possible.
In instances where patching is not immediately feasible, temporary mitigation can be achieved through the use of Web Application Firewalls (WAFs) or Intrusion Detection Systems (IDS). These tools can help detect and block attempts to exploit this vulnerability, providing a layer of protection while a more permanent solution is implemented.

Overview

The cybersecurity landscape is constantly evolving with new vulnerabilities being discovered and patched regularly. One such vulnerability, designated as CVE-2025-47953, affects the ubiquitous productivity software, Microsoft Office. This vulnerability could allow an unauthorized attacker to execute code locally, potentially compromising system security and leading to data leakage. Its severity and the widespread use of Microsoft Office make it a crucial area of focus for cybersecurity professionals and system administrators.

Vulnerability Summary

CVE ID: CVE-2025-47953
Severity: High (8.4 CVSS score)
Attack Vector: Local
Privileges Required: User
User Interaction: Required
Impact: System compromise and potential data leakage

Affected Products

Product | Affected Versions

Microsoft Office | All versions prior to the latest patch

How the Exploit Works

The vulnerability lies in the handling of memory objects in Microsoft Office. It’s a use-after-free vulnerability, where the software references memory after it has been freed or deleted. This can lead to undefined behavior such as crashing the program or, in this case, allows an attacker to execute arbitrary code. An attacker can craft a malicious document which, when opened by a user, triggers the use-after-free condition and executes the attacker’s code with the privileges of the current user.

Conceptual Example Code

The following is a conceptual example of a malicious payload that could be embedded in a document to exploit this vulnerability:

Sub AutoOpen()
Dim buffer As String
Dim Ptr As Long
Dim shellcode As String
' Create a buffer and free it
buffer = Space$(1000)
Ptr = VarPtr(buffer)
buffer = ""
' Use the freed buffer
shellcode = "<malicious shellcode>"
CopyMemory ByVal Ptr, ByVal StrPtr(shellcode), Len(shellcode)
' Trigger execution of shellcode
Execute Ptr
End Sub

This pseudo-code is a simplified representation, and actual shellcode would be specifically crafted to exploit the vulnerability and perform malicious actions such as installing malware or exfiltrating data.

Mitigation Guidance

To mitigate this vulnerability, users are advised to apply the vendor patch provided by Microsoft. Until the patch can be applied, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can provide temporary mitigation. These tools can detect and block attempts to exploit the vulnerability, reducing the risk of a successful attack.

Overview

In this article, we will delve into the details of a severe vulnerability that affects Microsoft Office, one of the world’s most widely used office productivity software suites. The vulnerability, identified as CVE-2025-47167, involves a type confusion flaw that could potentially allow an unauthorized attacker to execute code locally on a victim’s system.
This vulnerability matters because of the ubiquitous nature of Microsoft Office. With millions of users worldwide, both in personal and professional settings, a vulnerability of this nature could potentially lead to substantial data breaches and unauthorized system access. This underscores the need for rigorous cybersecurity measures and the importance of staying informed about the latest vulnerabilities and their mitigation strategies.

Vulnerability Summary

CVE ID: CVE-2025-47167
Severity: High (CVSS: 8.4)
Attack Vector: Local
Privileges Required: None
User Interaction: Required
Impact: Unauthorized local code execution leading to potential system compromise or data leakage

Affected Products

Product | Affected Versions

Microsoft Office | All Versions Up To Latest Patch

How the Exploit Works

The vulnerability originates from a type confusion flaw in Microsoft Office. An attacker can craft a malicious Microsoft Office document that abuses this flaw, effectively tricking the software into treating one type of data as if it were a different type. Once the document is opened by a user, the attacker’s code is executed locally on the user’s system.

Conceptual Example Code

Here is a conceptual example of how an attacker might exploit this vulnerability. It involves crafting a malicious payload within a Microsoft Word document.

Open New Microsoft Word Document
Embed Payload {
Type: 'Expected Data Type',
Content: 'Malicious Code'
}
Save Document as 'Compromised.docx'
Send 'Compromised.docx' to Target

In this pseudocode, the attacker creates a new Word document, embeds the malicious code within it (while presenting it as an expected data type), and then saves and sends the document to the target. When the target opens the document, the malicious code is executed.

Mitigation

The primary solution to this vulnerability is to apply the latest patches provided by Microsoft. Regularly updating your software ensures that you are protected against known vulnerabilities. For immediate, temporary mitigation, users can use a Web Application Firewall (WAF) or an Intrusion Detection System (IDS). These systems can detect and block attempts to exploit this vulnerability. However, these are not long-term solutions and should not replace the application of the vendor-provided patch.
Remember that in cybersecurity, staying updated is one of the most effective ways to protect your systems and data from threats.