CVE-2023-23392 Overview
CVE-2023-23392 is a remote code execution vulnerability in the Microsoft HTTP Protocol Stack (HTTP.sys). The flaw stems from a use-after-free condition [CWE-416] that an unauthenticated attacker can trigger by sending specially crafted HTTP/3 requests to a vulnerable target. Successful exploitation grants code execution in the context of the kernel, leading to full system compromise. The vulnerability affects modern Windows platforms with HTTP/3 and buffered I/O enabled, including Windows 11 and Windows Server 2022. Microsoft addressed the issue in the March 2023 security update cycle.
Critical Impact
Unauthenticated network attackers can achieve remote code execution at the kernel level, compromising confidentiality, integrity, and availability without user interaction.
Affected Products
- Microsoft Windows 11 version 21H2
- Microsoft Windows 11 version 22H2
- Microsoft Windows Server 2022
Discovery Timeline
- 2023-03-14 - CVE-2023-23392 published to the National Vulnerability Database
- 2024-11-21 - Last updated in NVD database
Technical Details for CVE-2023-23392
Vulnerability Analysis
The vulnerability resides in the Windows HTTP Protocol Stack, which processes inbound HTTP requests at the kernel level through the HTTP.sys driver. The component contains a use-after-free condition [CWE-416] in its handling of HTTP/3 traffic. An attacker reaches the affected code path by sending crafted requests across the network without authentication and without any user interaction on the target.
Because HTTP.sys runs in kernel mode, successful exploitation results in arbitrary code execution at the highest privilege level on the host. The vulnerability impacts any service that binds to the HTTP Protocol Stack, including Internet Information Services (IIS) and applications using the HttpListener API. The EPSS model places this CVE in the upper percentile for likelihood of exploitation activity.
Root Cause
The root cause is a use-after-free defect in HTTP.sys request processing logic. Specific code paths release a memory object while another execution path retains a reference to it, allowing the freed allocation to be reused with attacker-influenced data. When the dangling reference is dereferenced, the kernel operates on memory whose contents the attacker can shape, providing a primitive for code execution.
Attack Vector
The attack vector is purely network-based. An attacker sends a sequence of crafted HTTP/3 requests to any service exposing the vulnerable HTTP Protocol Stack on the network. No credentials, prior foothold, or user interaction is required. Internet-facing IIS servers and Windows hosts with HTTP/3 enabled present the largest exposure.
// No verified public proof-of-concept code is available for CVE-2023-23392.
// Refer to the Microsoft Security Response Center advisory for technical guidance.
Detection Methods for CVE-2023-23392
Indicators of Compromise
- Unexpected crashes or bug checks involving HTTP.sys in Windows Event Logs, particularly under HTTP/3 workloads.
- Anomalous outbound connections or new processes spawned by System or svchost.exe following inbound HTTP/3 traffic.
- Sudden creation of services, scheduled tasks, or local accounts on web-facing Windows servers.
Detection Strategies
- Monitor IIS and HTTP.sys for malformed HTTP/3 frames and abnormal request patterns directed at affected hosts.
- Correlate kernel-mode crashes with network telemetry showing HTTP/3 traffic from untrusted sources.
- Apply behavioral analytics to detect post-exploitation activity such as credential dumping or lateral movement originating from web server processes.
Monitoring Recommendations
- Enable HTTP logging and ETW tracing on the Microsoft-Windows-HttpService provider for forensic visibility.
- Forward Windows Security, System, and IIS logs to a centralized SIEM for correlation against threat intelligence.
- Track patch state of all Windows 11 and Windows Server 2022 systems exposing HTTP services on internal or external networks.
How to Mitigate CVE-2023-23392
Immediate Actions Required
- Apply the March 2023 Microsoft security updates to all Windows 11 21H2, Windows 11 22H2, and Windows Server 2022 systems.
- Inventory all hosts running IIS or custom services using HTTP.sys and prioritize internet-exposed assets for patching.
- Restrict inbound HTTP/3 traffic at the network edge until patching is verified across the environment.
Patch Information
Microsoft released fixes for CVE-2023-23392 in the March 2023 Patch Tuesday cycle. Refer to the Microsoft Vulnerability Advisory CVE-2023-23392 for the specific KB articles aligned to each affected Windows build.
Workarounds
- Disable HTTP/3 support on affected servers where the protocol is not required for business operations.
- Disable buffered I/O on HTTP/3 endpoints if HTTP/3 must remain enabled.
- Place vulnerable hosts behind a web application firewall or reverse proxy that does not pass HTTP/3 traffic to the origin server.
# Disable HTTP/3 on IIS by removing the EnableHttp3 registry value
reg delete "HKLM\SYSTEM\CurrentControlSet\Services\HTTP\Parameters" /v EnableHttp3 /f
# Restart the HTTP service to apply changes
net stop http /y && net start http
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
