CVE-2022-22035: Windows 10 PPTP RCE Vulnerability

CVE-2022-22035 Overview

CVE-2022-22035 is a remote code execution vulnerability in the Windows Point-to-Point Tunneling Protocol (PPTP) implementation. This race condition vulnerability (CWE-362) affects a wide range of Microsoft Windows operating systems, including both client and server editions. An unauthenticated attacker could exploit this vulnerability by sending specially crafted PPTP packets to a vulnerable Windows system, potentially gaining the ability to execute arbitrary code with elevated privileges.

Critical Impact

Successful exploitation allows remote attackers to execute arbitrary code on vulnerable Windows systems without authentication, potentially compromising the entire system and any connected network resources.

Affected Products

• Microsoft Windows 10 (multiple versions including 20H2, 21H1, 21H2, 1607, 1809)
• Microsoft Windows 11 (including 22H2)
• Microsoft Windows 7 SP1
• Microsoft Windows 8.1
• Microsoft Windows RT 8.1
• Microsoft Windows Server 2008 SP2 and R2 SP1
• Microsoft Windows Server 2012 and R2
• Microsoft Windows Server 2016
• Microsoft Windows Server 2019
• Microsoft Windows Server 2022

Discovery Timeline

• October 11, 2022 - CVE-2022-22035 published to NVD
• January 2, 2025 - Last updated in NVD database

Technical Details for CVE-2022-22035

Vulnerability Analysis

This vulnerability exists within the Windows implementation of the Point-to-Point Tunneling Protocol (PPTP), a legacy VPN protocol used for secure remote access connections. The flaw is classified as a race condition (CWE-362), where improper synchronization of concurrent operations creates a window of opportunity for exploitation.

The vulnerability can be triggered remotely over the network without requiring user interaction or prior authentication. However, the attack complexity is high due to the precise timing requirements inherent to race condition exploitation. When successfully exploited, an attacker can achieve complete system compromise with the ability to read, modify, or delete data, install programs, and create new accounts with full user rights.

Root Cause

The root cause of CVE-2022-22035 is a race condition (CWE-362) in the PPTP protocol handler within the Windows kernel or associated network drivers. Race conditions occur when the timing or ordering of events affects the correctness of a program, and multiple threads or processes access shared resources without proper synchronization mechanisms.

In this case, the PPTP implementation fails to properly serialize access to shared data structures during connection handling. When processing specially crafted network packets with specific timing, an attacker can cause the system to operate on memory that is in an inconsistent state, leading to memory corruption and ultimately remote code execution.

Attack Vector

The attack vector for CVE-2022-22035 is network-based. An attacker can exploit this vulnerability remotely by:

1. Identifying a target system with PPTP services enabled or exposed
2. Sending specially crafted PPTP connection requests to the target
3. Timing the malicious packets to trigger the race condition during packet processing
4. Leveraging the resulting memory corruption to execute arbitrary code

The attack does not require authentication or user interaction, making it particularly dangerous for systems with PPTP services exposed to untrusted networks. However, the high complexity requirement means reliable exploitation requires precise timing control, which may reduce the practical exploitability in some network environments.

Detection Methods for CVE-2022-22035

Indicators of Compromise

• Unusual PPTP traffic patterns on TCP port 1723 or GRE protocol traffic from unexpected sources
• Unexpected process spawning or code execution following PPTP connection attempts
• System crashes or blue screens related to network driver components (raspptp.sys)
• Memory corruption artifacts or anomalous kernel memory access patterns

Detection Strategies

• Monitor network traffic for abnormal PPTP connection requests, particularly those with malformed or unusually timed packets
• Deploy endpoint detection solutions like SentinelOne to identify exploitation attempts through behavioral analysis
• Enable Windows Security Events logging and monitor for suspicious process creation events following network activity
• Implement intrusion detection/prevention system (IDS/IPS) rules targeting PPTP protocol anomalies

Monitoring Recommendations

• Enable detailed logging for VPN services and PPTP connections on Windows systems
• Monitor for crash dumps or error reports related to raspptp.sys or other PPTP-related components
• Track system stability metrics on servers with PPTP enabled, as exploitation attempts may cause system instability
• Correlate network traffic logs with endpoint security events to identify potential attack chains

How to Mitigate CVE-2022-22035

Immediate Actions Required

• Apply Microsoft security updates released in October 2022 Patch Tuesday immediately to all affected systems
• If patching is not immediately possible, consider disabling PPTP services until patches can be applied
• Block PPTP traffic (TCP port 1723 and GRE protocol) at network perimeter firewalls for systems that do not require this functionality
• Migrate from PPTP to more secure VPN protocols such as IKEv2, L2TP/IPSec, or SSTP

Patch Information

Microsoft has released security updates to address this vulnerability as part of the October 2022 security updates. Patches are available for all affected Windows versions through Windows Update, WSUS, and the Microsoft Update Catalog.

For detailed patch information and download links, refer to the Microsoft Security Update Guide for CVE-2022-22035 or the Microsoft Security Response Center Advisory.

Organizations should prioritize patching systems that have PPTP services enabled or exposed to untrusted networks.

Workarounds

• Disable PPTP VPN services on systems where this functionality is not required by stopping and disabling the Remote Access Connection Manager service
• Use Windows Firewall to block inbound PPTP connections (TCP port 1723 and GRE protocol 47) on vulnerable systems
• Implement network segmentation to isolate systems requiring PPTP from direct internet exposure
• Consider transitioning to modern VPN solutions that use more secure protocols and do not rely on PPTP

# Disable PPTP by blocking at Windows Firewall
netsh advfirewall firewall add rule name="Block PPTP TCP" dir=in action=block protocol=tcp localport=1723
netsh advfirewall firewall add rule name="Block GRE Protocol" dir=in action=block protocol=47

# Disable Remote Access Connection Manager service
sc config RasMan start= disabled
sc stop RasMan