CVE-2022-36937
📋 TL;DR
This vulnerability in HHVM allows attackers to intercept or manipulate encrypted network communications by forcing the use of deprecated TLS 1.0 protocol. Applications using HHVM's stream extension with tls:// URLs for secure connections are affected. The risk is particularly high for systems handling sensitive data over network connections.
💻 Affected Systems
- HHVM
📦 What is this software?
Hhvm by Facebook
Hhvm by Facebook
Hhvm by Facebook
Hhvm by Facebook
Hhvm by Facebook
Hhvm by Facebook
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of encrypted communications, allowing man-in-the-middle attacks to intercept, decrypt, and modify sensitive data including authentication credentials, financial information, and personal data.
Likely Case
Successful man-in-the-middle attacks leading to data interception and potential credential theft when attackers can position themselves between client and server.
If Mitigated
Limited impact if network segmentation prevents man-in-the-middle positioning and if additional encryption layers are used, though TLS 1.0 vulnerabilities remain exploitable.
🎯 Exploit Status
Exploitation requires man-in-the-middle positioning but uses well-known TLS 1.0 vulnerabilities. No public exploit code identified but trivial to implement given known TLS 1.0 weaknesses.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 4.153.4, 4.168.2, 4.169.2, 4.170.2, 4.171.1, 4.172.1, 4.173.0 and later
Vendor Advisory: https://hhvm.com/blog/2023/01/20/security-update.html
Restart Required: Yes
Instructions:
1. Identify HHVM version currently running. 2. Upgrade to patched version (4.153.4, 4.168.2, 4.169.2, 4.170.2, 4.171.1, 4.172.1, or 4.173.0+). 3. Restart HHVM service. 4. Verify TLS 1.3 is being used for tls:// connections.
🔧 Temporary Workarounds
Disable tls:// stream usage
allModify applications to avoid using stream_socket_server or stream_socket_client with tls:// URLs
# Review application code for tls:// usage in stream functions
# Replace with alternative secure communication methods
Network-level TLS enforcement
linuxUse network appliances or proxies to enforce TLS 1.2+ and block TLS 1.0 connections
# Configure load balancers or proxies to require TLS 1.2+
# Example for nginx: ssl_protocols TLSv1.2 TLSv1.3;
🧯 If You Can't Patch
- Implement network segmentation to prevent man-in-the-middle attacks
- Add application-layer encryption for sensitive data transmitted via tls:// streams
🔍 How to Verify
Check if Vulnerable:
Check HHVM version and review application code for stream_socket_server or stream_socket_client calls with tls:// URLsCheck Version:
hhvm --versionVerify Fix Applied:
Test tls:// connections and verify TLS 1.3 is being negotiated using tools like openssl s_client or network packet inspection📡 Detection & Monitoring
Log Indicators:
- TLS 1.0 handshake attempts in network logs
- Unexpected connection failures after TLS protocol changes
Network Indicators:
- TLS 1.0 protocol usage on ports where HHVM tls:// connections are expected
- Man-in-the-middle attack patterns in network traffic
SIEM Query:
source="network_traffic" protocol="TLS" tls_version="1.0" dest_port IN (443, 8443, [your_app_ports])