CVE-2024-41270: Gorush Information Disclosure Vulnerability

CVE-2024-41270 Overview

A critical cryptographic vulnerability has been discovered in Gorush, a popular Go-based push notification server. The vulnerability exists in the RunHTTPServer function in Gorush v1.18.4, where the use of a deprecated TLS version allows attackers to intercept and manipulate data transmitted between the server and clients.

Critical Impact

This vulnerability enables network-based attackers to perform man-in-the-middle attacks without authentication, potentially compromising confidential push notification data and allowing manipulation of message content.

Affected Products

• Appleboy Gorush v1.18.4
• Gorush versions using deprecated TLS configurations
• Go-based push notification deployments utilizing vulnerable Gorush builds

Discovery Timeline

• 2024-08-06 - CVE CVE-2024-41270 published to NVD
• 2024-08-12 - Last updated in NVD database

Technical Details for CVE-2024-41270

Vulnerability Analysis

This vulnerability falls under CWE-327 (Use of a Broken or Risky Cryptographic Algorithm). The RunHTTPServer function in Gorush v1.18.4 is configured to use deprecated TLS protocol versions that are known to be insecure. When the HTTP server starts with TLS enabled, the cryptographic configuration does not enforce modern TLS standards, leaving connections vulnerable to protocol downgrade attacks and cryptanalysis.

The vulnerability allows network-adjacent attackers to intercept HTTPS traffic between clients and the Gorush server. Since push notification services often transmit sensitive information including device tokens, message payloads, and authentication credentials, successful exploitation could lead to significant data exposure and message tampering.

Root Cause

The root cause lies in the TLS configuration within the RunHTTPServer function, which permits the use of deprecated TLS versions (likely TLS 1.0 or TLS 1.1) instead of enforcing TLS 1.2 or TLS 1.3 as minimum requirements. Modern security standards recommend deprecating TLS versions below 1.2 due to known vulnerabilities such as BEAST, POODLE, and various cipher suite weaknesses.

Go's crypto/tls package provides configuration options to set minimum and maximum TLS versions, but the vulnerable Gorush version fails to properly configure these settings, defaulting to accepting older, insecure protocol versions.

Attack Vector

The attack can be performed over the network without requiring authentication or user interaction. An attacker positioned between the Gorush server and its clients can:

1. Perform a protocol downgrade attack to force the use of a deprecated TLS version
2. Exploit known weaknesses in the deprecated TLS protocol to decrypt traffic
3. Intercept push notification payloads, device tokens, and API credentials
4. Potentially inject or modify push notification content in transit

The vulnerability is particularly dangerous in environments where push notifications contain sensitive business data or where the Gorush server handles notifications for multiple applications.

A proof-of-concept demonstrating the vulnerability is available in the GitHub Gist published by nyxfqq. Administrators should review this technical reference to understand the exploitation mechanism and validate their configurations.

Detection Methods for CVE-2024-41270

Indicators of Compromise

• Unusual TLS negotiation patterns indicating protocol downgrade attempts
• Network traffic using TLS 1.0 or TLS 1.1 to/from the Gorush server
• Unexpected client certificate warnings or SSL/TLS errors in application logs
• Evidence of man-in-the-middle proxy infrastructure targeting push notification endpoints

Detection Strategies

• Monitor TLS handshake logs for connections using protocol versions below TLS 1.2
• Implement network-based detection for TLS downgrade attack signatures
• Review Gorush server access logs for connections from unexpected intermediary IP addresses
• Deploy SSL/TLS inspection capabilities to identify weak cipher suite negotiations

Monitoring Recommendations

• Enable verbose TLS logging on the Gorush server to track protocol version usage
• Configure network monitoring tools to alert on deprecated TLS version usage
• Implement certificate transparency monitoring for any certificates used by Gorush
• Set up periodic security scans to verify TLS configuration compliance

How to Mitigate CVE-2024-41270

Immediate Actions Required

• Upgrade Gorush to a patched version that enforces TLS 1.2 or higher as the minimum protocol version
• Review and update TLS configuration to disable deprecated protocol versions
• Audit network infrastructure for any signs of man-in-the-middle positioning
• Rotate any API credentials or tokens that may have been transmitted over vulnerable connections

Patch Information

Organizations should monitor the official Gorush repository for security updates addressing this vulnerability. Until an official patch is released, administrators should implement the TLS configuration workarounds outlined below to enforce modern cryptographic standards.

Workarounds

• Configure the Go TLS settings to explicitly require TLS 1.2 as the minimum version by setting MinVersion: tls.VersionTLS12 in the TLS configuration
• Deploy a reverse proxy (such as nginx or HAProxy) with properly configured TLS termination in front of Gorush
• Implement network segmentation to limit exposure of the Gorush server to trusted networks only
• Consider using mutual TLS (mTLS) to add an additional layer of authentication for client connections

# Configuration example for nginx reverse proxy with secure TLS
# Place in front of Gorush to enforce TLS 1.2+

ssl_protocols TLSv1.2 TLSv1.3;
ssl_prefer_server_ciphers on;
ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384;
ssl_session_timeout 1d;
ssl_session_cache shared:SSL:50m;
ssl_stapling on;
ssl_stapling_verify on;