Microsoft Office365 Integrity Validation / Remote Code Execution

2019.11.05
Risk: High
Local: No
Remote: Yes
CVE: N/A
CWE: CWE-325

# Exploit Title: Microsoft Office365 Remote Code Execution Vulnerability # Date: 2/11/19 # Exploit Author: Social Engineering Neo - @EngineeringNeo # Vendor Homepage: https://microsoft.com # Software Link: https://office.com # Version: Office365/ProPlus (build 16.0.11727.20222, 16.0.11901.20170, 16.0.11901.20204 & 16.0.11929.202.88) # Tested on: Windows 10 (build 17763.253, 18362.295 & 18362.356) Affected Platforms: - Microsoft Windows ≤10 Office365 & ProPlus Products ≤2019 Tested On: - Windows 10 (build 17763.253, 18362.295 & 18362.356) Office365/ProPlus (build 16.0.11727.20222, 16.0.11901.20170, 16.0.11901.20204 & 16.0.11929.202.88) Most up to-date version of Microsoft Windows & Office365/ProPlus Products are affected. Base: - CWE-325 - Missing Required Cryptographic Step. The software does not implement a required step in a cryptographic algorithm used to validate the original integrity of documents. Summary: - Improper Integrity Validation of Office Documents Resulting in Multiple Microsoft Office Products Suffering from a Protection Bypass Vulnerability. Allowing Auto-Execution of Macro Code Inside Macro-Enabled Office Documents. Short Description: - Overwriting an original macro-enabled document with a malicious document will bypass the built-in protections. Long Description: - A user creates a macro-enabled MS Word document and saves the document with text/data inside. If the user deletes the document and downloads a completely different document with the same name, this can allow remote code execution. When a document is opened/edited, Office apps keep a record of the name and permissions associated with the specific document. This can be abused when downloading a malicious document to run code remotely on the machine. Proof of Concept: - ===== Tested on Latest Versions of Access, Excel, InfoPath, OneNote, Outlook, PowerPoint, Project, Publisher, Visio, Word. Affects Access, Excel, InfoPath, PowerPoint, Visio, Word. Does not affect OneNote, Outlook, Project, Publisher. ATTACKER: - Step 0.) - Knowledge of Office document names on VICTIM device. Step 1.) - Inject malicious VBA macro code & payload into Office document. *preferably AV evasive* Step 2.) - Send malicious macro-enabled document to VICTIM through internet. Step 3.) - Setup bind/reverse connection. VICTIM: - Step 1.) - Download document sent by ATTACKER. Step 2.) - Open Document in same location as previous document. [CODE EXECUTION SUCCESSFUL] VIDEO: - https://youtu.be/YVF7gqWZSGE ===== Expected Result: - It shouldn't be possible to automatically execute macro code on the host machine without user consent or additional configuration. (Clean Install) Observed Result: - Office document auto-executes macro code upon loading document without any user consent, in our case leading to remote code execution. (User Level Access)


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