CVE-2023-23397: Microsoft Outlook Privilege Escalation

CVE-2023-23397 Overview

Microsoft Outlook Elevation of Privilege Vulnerability

Critical Impact

This vulnerability allows unauthorized users to gain elevated privileges, potentially compromising the confidentiality, integrity, and availability of targeted systems.

Affected Products

• microsoft 365_apps
• microsoft office
• microsoft office_long_term_servicing_channel
• microsoft outlook

Discovery Timeline

• 2023-03-14T17:15:13.263 - CVE CVE-2023-23397 published to NVD
• 2025-10-27T17:14:31.953 - Last updated in NVD database

Technical Details for CVE-2023-23397

Vulnerability Analysis

The vulnerability involves improper input validation that leads to an elevation of privilege. An attacker could exploit this flaw by sending a crafted email, which is processed by Microsoft Outlook, triggering malicious behavior.

Root Cause

The root cause of this vulnerability is associated with improper handling of certain attributes within email objects processed by Outlook.

Attack Vector

This is a network-based attack, where a remote attacker sends specially crafted emails to target systems running vulnerable versions of Microsoft Outlook.

# Example exploitation code (sanitized)
# The attacker sends a specially crafted email
send-mailmessage -to [email protected] \
   -subject "Critical Meeting Update" \
   -body "Please review the attached document." \
   -smtpserver attacker.com

Detection Methods for CVE-2023-23397

Indicators of Compromise

• Unusual email activity originating from unknown sources
• Logs indicating unauthorized access attempts
• Detection of unknown email rules created within the client

Detection Strategies

Leverage endpoint security tools to monitor for known malicious signatures and behaviours indicative of exploitation attempts involving Microsoft Outlook email processing.

Monitoring Recommendations

Implement monitoring of email traffic for anomalous patterns and deploy intrusion detection systems capable of analyzing email content and headers for suspicious attributes.

How to Mitigate CVE-2023-23397

Immediate Actions Required

• Apply the latest security patches provided by Microsoft
• Educate users on recognizing phishing attempts
• Enable and enforce MFA (Multi-Factor Authentication)

Patch Information

Microsoft has released a security update addressing this vulnerability in Microsoft Outlook. Ensure all outlook clients are updated with this patch.

Workarounds

Administrators can create transport rules to filter emails showing patterns consistent with those used in attacks targeting this vulnerability.

# Configuration example
Set-TransportRule \ 
   -Name "Block Potentially Malicious Emails" \ 
   -SubjectOrBodyContainsWords @("Critical Meeting Update") \ 
   -RejectMessageReasonText "Blocked for security reasons"