CVE-2023-36028: Windows 10 1507 PEAP RCE Vulnerability

CVE-2023-36028 Overview

CVE-2023-36028 is a critical remote code execution vulnerability affecting Microsoft's Protected Extensible Authentication Protocol (PEAP) implementation across a wide range of Windows operating systems. PEAP is a widely deployed authentication protocol used primarily for wireless network authentication and VPN connections, making this vulnerability particularly impactful for enterprise environments.

The vulnerability allows an unauthenticated remote attacker to execute arbitrary code on affected systems without any user interaction. This makes it especially dangerous in scenarios where PEAP is used for network authentication, as attackers could potentially compromise systems during the authentication process itself.

Critical Impact

Remote code execution vulnerability in PEAP allows unauthenticated attackers to execute arbitrary code on affected Windows systems without user interaction, potentially compromising network authentication infrastructure.

Affected Products

• Microsoft Windows 10 (versions 1507, 1607, 1809, 21H2, 22H2)
• Microsoft Windows 11 (versions 21H2, 22H2, 23H2)
• Microsoft Windows Server 2016, 2019, 2022

Discovery Timeline

• November 14, 2023 - CVE-2023-36028 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2023-36028

Vulnerability Analysis

This vulnerability is classified as a Heap-based Buffer Overflow (CWE-122), which occurs in the PEAP authentication handling component of Windows. The flaw exists in how the PEAP protocol processes specially crafted authentication messages, allowing attackers to trigger memory corruption conditions.

The vulnerability requires no privileges and no user interaction to exploit, and it can be triggered remotely over the network. This combination makes it particularly dangerous for organizations relying on PEAP for wireless or VPN authentication. An attacker successfully exploiting this vulnerability could gain the same privileges as the process handling PEAP authentication, which typically runs with elevated system privileges.

Root Cause

The root cause is a heap-based buffer overflow (CWE-122) in the Microsoft PEAP implementation. When processing authentication protocol messages, the code fails to properly validate the length of incoming data before copying it to a fixed-size heap buffer. This allows an attacker to overflow the allocated buffer and overwrite adjacent memory structures, potentially gaining control of program execution flow.

Attack Vector

The attack vector is network-based, targeting systems that have PEAP authentication enabled. An attacker can exploit this vulnerability by:

1. Setting up a malicious access point or RADIUS server
2. Enticing or forcing a vulnerable client to connect
3. Sending specially crafted PEAP messages during the authentication handshake
4. Triggering the heap overflow to achieve code execution

Alternatively, if the attacker can position themselves in a man-in-the-middle scenario, they could inject malicious PEAP messages into legitimate authentication sessions. The vulnerability can be exploited without authentication, meaning any network-accessible system with PEAP enabled is potentially at risk.

The exploitation process involves crafting malicious EAP-TLV (Type-Length-Value) messages with oversized length fields that overflow heap-allocated buffers during PEAP session processing. Detailed technical analysis is available in the Microsoft Security Update Guide.

Detection Methods for CVE-2023-36028

Indicators of Compromise

• Unexpected crashes or restarts of network authentication services (NPS/RADIUS)
• Anomalous EAP/PEAP traffic patterns with malformed or oversized TLV structures
• Suspicious process spawning from svchost.exe handling network authentication
• Memory access violations in Windows Event logs related to EAP components

Detection Strategies

• Deploy network intrusion detection rules to identify malformed PEAP authentication packets
• Monitor Windows Event logs for application crashes in Network Policy Server (NPS) or related authentication services
• Implement endpoint detection for anomalous behavior following wireless network connections
• Use SentinelOne's behavioral AI to detect exploitation attempts targeting PEAP authentication

Monitoring Recommendations

• Enable detailed logging for Network Policy Server (NPS) and RADIUS authentication events
• Monitor for unusual authentication failures or protocol anomalies on wireless access points
• Configure alerts for system service crashes related to eaphost.dll or authentication components
• Implement network traffic analysis for EAP protocol anomalies at network boundaries

How to Mitigate CVE-2023-36028

Immediate Actions Required

• Apply Microsoft's November 2023 security updates to all affected Windows systems immediately
• Prioritize patching systems running Network Policy Server (NPS) or RADIUS services
• Audit all systems using PEAP for wireless or VPN authentication and ensure they are updated
• Consider temporarily disabling PEAP authentication and using alternative methods if patching is delayed

Patch Information

Microsoft has released security updates addressing this vulnerability as part of the November 2023 Patch Tuesday release. Organizations should apply the appropriate updates for their Windows versions immediately. The official security update information is available in the Microsoft Security Update Guide for CVE-2023-36028.

Use Windows Update, Windows Server Update Services (WSUS), or Microsoft Endpoint Configuration Manager to deploy the patches across your environment. Ensure all Windows versions including Windows 10 (all supported versions), Windows 11, and Windows Server 2016/2019/2022 are updated.

Workarounds

• Disable PEAP authentication temporarily and use alternative EAP methods such as EAP-TLS where possible
• Implement network segmentation to limit exposure of authentication infrastructure
• Use certificate-based authentication methods that do not rely on PEAP
• Restrict network access to known and trusted wireless access points and RADIUS servers

# Check current EAP/PEAP configuration on Windows Server NPS
netsh nps show config

# Verify Windows Update installation status
wmic qfe list brief | findstr /i "KB"

# Review installed updates for November 2023 security patches
Get-HotFix | Where-Object {$_.InstalledOn -gt "2023-11-01"} | Format-Table -AutoSize