Cybersecurity Vulnerabilities

Critical Vulnerability in Syrotech GPON Routers Exposes SSL Keys (CVE-2025-63729)

Overview

CVE-2025-63729 is a critical security vulnerability affecting Syrotech SY-GPON-1110-WDONT routers running firmware version SYRO_3.7L_3.1.02-240517. This vulnerability allows attackers to extract sensitive information, including the SSL Private Key, CA Certificate, SSL Certificate, and Client Certificates, from the firmware located in the /etc folder. This exposure poses a significant risk to the confidentiality and integrity of communications secured by these certificates.

Technical Details

The vulnerability stems from insufficient access control and protection mechanisms for sensitive files within the router’s firmware. Specifically, the SSL Private Key, CA Certificate, SSL Certificate, and Client Certificates are stored in .pem format within the /etc directory, without adequate security measures to prevent unauthorized access. An attacker who can access the firmware image (e.g., through a separate vulnerability or insider access) can easily extract these certificates.

Firmware version affected: SYRO_3.7L_3.1.02-240517

CVSS Analysis

  • CVE ID: CVE-2025-63729
  • Severity: CRITICAL
  • CVSS Score: 9.0

A CVSS score of 9.0 indicates that this vulnerability is highly critical. The ability to extract SSL keys and certificates allows for a wide range of attacks, including man-in-the-middle attacks, decryption of network traffic, and impersonation of the router or its clients.

Possible Impact

The exploitation of CVE-2025-63729 can lead to severe consequences:

  • Man-in-the-Middle Attacks: Attackers can intercept and modify network traffic between the router and its clients.
  • Data Decryption: Sensitive data transmitted over encrypted connections can be decrypted, compromising user privacy and security.
  • Impersonation: Attackers can impersonate the router or its clients, gaining unauthorized access to services and resources.
  • Compromised VPN connections: SSL keys used for VPN connections can be extracted, allowing an attacker to establish rogue VPN tunnels and intercept traffic.
  • Loss of Trust: Customers may lose trust in the Syrotech brand, leading to financial losses and reputational damage.

Mitigation and Patch Steps

Currently, there is no official patch available from Syrotech for this vulnerability. Users are advised to take the following steps:

  • Contact Syrotech Support: Contact Syrotech support and request an updated firmware version that addresses this vulnerability.
  • Network Segmentation: Isolate the affected Syrotech routers from critical network segments to limit the potential impact of a successful attack.
  • Monitor Network Traffic: Implement network intrusion detection systems (IDS) to monitor for suspicious activity and potential exploitation attempts.
  • Secure Router Access: Ensure that access to the router’s web interface is protected with strong passwords and two-factor authentication (if available). Restrict remote management access where possible.
  • Disable unnecessary services: Disable any unnecessary services running on the router.

We will update this article as soon as a patch is released by Syrotech.

References

Cybersecurity specialist and founder of Gowri Shankar Infosec - a professional blog dedicated to sharing actionable insights on cybersecurity, data protection, server administration, and compliance frameworks including SOC 2, PCI DSS, and GDPR.

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