CVE-2025-47162: Microsoft 365 Apps Buffer Overflow Flaw

CVE-2025-47162 Overview

CVE-2025-47162 is a heap-based buffer overflow vulnerability affecting Microsoft Office products that allows an unauthorized attacker to execute arbitrary code locally. This memory corruption flaw (CWE-122) occurs when Office applications improperly handle memory operations, enabling attackers to corrupt heap memory and potentially gain control over program execution flow.

Critical Impact

Successful exploitation could allow attackers to execute arbitrary code with the privileges of the current user, potentially leading to complete system compromise, data theft, or lateral movement within enterprise environments.

Affected Products

• Microsoft 365 Apps for Enterprise
• Microsoft Office 2016, 2019
• Microsoft Office for Android
• Microsoft Office Long Term Servicing Channel 2021 (Windows and macOS)
• Microsoft Office Long Term Servicing Channel 2024 (Windows and macOS)

Discovery Timeline

• 2025-06-10 - CVE-2025-47162 published to NVD
• 2025-07-09 - Last updated in NVD database

Technical Details for CVE-2025-47162

Vulnerability Analysis

This vulnerability stems from improper memory management within Microsoft Office applications. When processing certain data structures, the affected Office components fail to properly validate buffer boundaries during heap memory operations. This allows an attacker to trigger a heap-based buffer overflow condition by crafting malicious input that causes the application to write data beyond the allocated heap buffer.

The local attack vector means that exploitation requires the attacker to either have local access to the target system or to convince a user to open a maliciously crafted document. No user interaction is required beyond opening the malicious file, and no special privileges are needed to trigger the vulnerability, making it relatively straightforward to exploit once an attacker can deliver the payload.

Root Cause

The root cause is classified as CWE-122: Heap-based Buffer Overflow. This occurs when data is written beyond the boundaries of allocated heap memory. In Microsoft Office, this likely manifests during document parsing or rendering operations where input data length is not properly validated before being copied into fixed-size heap buffers. The overflow can corrupt adjacent heap metadata or application data, which attackers can leverage to achieve code execution.

Attack Vector

The vulnerability requires local access to exploit (Attack Vector: Local). An attacker would typically need to:

1. Craft a malicious Office document containing specially crafted data designed to trigger the heap overflow
2. Deliver the document to the victim through email attachments, file shares, or other distribution methods
3. Convince the victim to open the document in a vulnerable Microsoft Office application
4. Upon opening, the malicious content triggers the heap overflow, corrupting memory
5. The corrupted memory state allows the attacker to redirect execution flow and run arbitrary code

The exploitation does not require elevated privileges and can be triggered without additional user interaction beyond opening the document. The impact includes potential compromise of confidentiality, integrity, and availability of the affected system.

Detection Methods for CVE-2025-47162

Indicators of Compromise

• Unexpected crashes or instability in Microsoft Office applications (Word, Excel, PowerPoint, Outlook)
• Suspicious Office document files with unusual internal structures or embedded objects
• Memory access violations or heap corruption errors in Office process crash dumps
• Anomalous child processes spawned from Office applications (e.g., cmd.exe, powershell.exe, mshta.exe)

Detection Strategies

• Monitor for Office applications exhibiting abnormal memory allocation patterns or heap corruption indicators
• Implement endpoint detection rules to identify Office processes spawning suspicious child processes
• Deploy document scanning solutions to analyze Office files before they reach end users
• Enable Windows Defender Exploit Guard features including Heap Integrity Validation and Code Flow Guard

Monitoring Recommendations

• Enable and review Windows Event Logs for Application Crash events (Event ID 1000, 1001) involving Office applications
• Configure SentinelOne Deep Visibility to monitor Office process behavior and memory operations
• Implement file integrity monitoring on common document landing zones (Downloads, Email attachments)
• Establish baseline Office application behavior to detect anomalies indicative of exploitation attempts

How to Mitigate CVE-2025-47162

Immediate Actions Required

• Apply the latest Microsoft security updates for all affected Office products immediately
• Enable Microsoft Office Protected View to prevent automatic execution of potentially malicious content
• Block Office documents from untrusted sources at the email gateway and web proxy levels
• Ensure SentinelOne agents are updated with the latest detection signatures and behavioral AI models

Patch Information

Microsoft has released security updates to address this vulnerability. Organizations should apply patches through their standard update mechanisms:

• Microsoft 365 Apps: Updates are delivered automatically through the Office deployment infrastructure
• Office 2016/2019: Install updates via Windows Update, WSUS, or Microsoft Update Catalog
• Office LTSC 2021/2024: Apply updates through volume licensing service center or update channels

For detailed patch information and download links, refer to the Microsoft Security Update Guide.

Workarounds

• Enable Protected View for files originating from the Internet, unsafe locations, or Outlook attachments
• Disable the opening of Office documents from untrusted locations via Group Policy
• Implement application whitelisting to prevent unauthorized code execution from Office processes
• Configure Attack Surface Reduction rules in Microsoft Defender to block Office applications from creating child processes

# Example: Enable Protected View settings via PowerShell for Office
# Configure registry settings to enforce Protected View

# Enable Protected View for Internet files
Set-ItemProperty -Path "HKCU:\Software\Microsoft\Office\16.0\Word\Security\ProtectedView" -Name "DisableInternetFilesInPV" -Value 0 -Type DWord

# Enable Protected View for Outlook attachments
Set-ItemProperty -Path "HKCU:\Software\Microsoft\Office\16.0\Word\Security\ProtectedView" -Name "DisableAttachmentsInPV" -Value 0 -Type DWord

# Enable Protected View for unsafe locations
Set-ItemProperty -Path "HKCU:\Software\Microsoft\Office\16.0\Word\Security\ProtectedView" -Name "DisableUnsafeLocationsInPV" -Value 0 -Type DWord