CVE-2025-7503 (CVSS 10): Root Access via Hidden Backdoor in IP Camera

Estimated reading time: 7 minutes

Key takeaways:

  • Critical vulnerability (CVE-2025-7503) in Shenzhen Liandian IP cameras allows root access.
  • Undocumented Telnet service with hard-coded credentials exposes the vulnerability.
  • Lack of vendor support necessitates proactive security measures.
  • PurpleOps services can help mitigate such threats through threat intelligence and supply-chain risk monitoring.

Table of Contents:

A critical vulnerability, CVE-2025-7503 (CVSS 10), has been identified in Shenzhen Liandian IP cameras, potentially allowing attackers to gain root access. This blog post details the specifics of this vulnerability, its impact, and potential mitigation strategies, highlighting how PurpleOps can assist in defending against such threats using our suite of services, including a cyber threat intelligence platform, dark web monitoring service, and supply-chain risk monitoring.

CVE-2025-7503: Undocumented Telnet Service Exposes Root Access

The vulnerability, CVE-2025-7503, resides in the firmware of Shenzhen Liandian Communication Technology LTD IP cameras. This flaw carries a CVSSv4 score of 10.0, signifying maximum severity. It allows unauthorized attackers to gain root-level access through an undocumented Telnet service.

Specifically, the affected firmware (AppFHE1_V1.0.6.0) and its associated kernel (KerFHE1_PTZ_WIFI_V3.1.1) and hardware (HwFHE1_WF6_PTZ_WIFI_20201218) expose a Telnet service on port 23. This service is:

  • Enabled by default.
  • Undocumented in the user manual.
  • Inaccessible via the web interface or mobile application.

Compounding the issue, attackers can connect to this Telnet service using hard-coded credentials, granting immediate root shell access. The CVE description explicitly states that *”an attacker with network access can authenticate using default credentials and gain root-level shell access to the device.”*

Lack of Vendor Support

Security researchers have been unable to contact the vendor, and no firmware patch or official advisory has been released. The report emphasizes that the *”Vendor does not provide a way to disable Telnet.”* There is no option to modify or remove the credentials, and no user interface feature to disable the Telnet service.

This absence of vendor support leaves users in a precarious situation, emphasizing the importance of proactive security measures.

Potential Impact of Root Access

Gaining root shell access allows an attacker to:

  • View or redirect live camera feeds, compromising privacy and security.
  • Modify the filesystem, potentially installing malware or tampering with device settings.
  • Launch network-based attacks from the compromised device, using it as a pivot point for further intrusion.
  • Implant persistent malware or backdoors, ensuring continued access even after a reboot.

The implications of CVE-2025-7503 extend beyond a single camera model, revealing a broader issue with low-cost, OEM-manufactured IoT devices, which often contain undocumented features and insecure defaults. This highlights the critical need for robust supply-chain risk monitoring to identify and mitigate vulnerabilities in third-party devices.

The advisory warns that *”Root shell access allows complete control over the device, including filesystem, networking, and camera feeds.”* In large installations, such as offices, schools, or public spaces, this level of access could enable surveillance, manipulation, or use of the cameras as entry points for internal network attacks. The attacker can perform network reconnaissance, deploy malicious payloads, and potentially compromise other systems on the same network.

This situation shows the importance of a comprehensive cyber threat intelligence platform that proactively identifies and assesses such vulnerabilities, allowing organizations to take swift action.

Root access exploitation on exposed IP camera

Mitigation Strategies

Given the lack of a vendor fix, affected users must implement defensive measures to reduce the risk associated with this vulnerability.

  1. Network Segmentation: Isolate IP cameras from the main network using VLANs (Virtual LANs). This limits the potential impact of a compromised camera on other systems.
  2. Firewall Rules: Block Telnet (port 23) at the network level via firewall rules. This prevents unauthorized access to the vulnerable service.
  3. Traffic Monitoring: Monitor outbound traffic for unusual behavior. This can help detect if a camera has been compromised and is being used for malicious purposes.
  4. Device Replacement: If hardened security and vendor support are essential, consider replacing the affected devices with more secure alternatives.

These measures can significantly reduce the attack surface and mitigate the risk posed by CVE-2025-7503.

Connection to PurpleOps Services

The vulnerability highlighted by CVE-2025-7503 underscores the importance of the services PurpleOps offers:

  • Cyber Threat Intelligence Platform: Our platform provides real-time updates on emerging threats and vulnerabilities, including those affecting IoT devices. This allows organizations to proactively identify and address potential risks.
  • Supply-Chain Risk Monitoring: We assess the security posture of third-party vendors and their products, identifying vulnerabilities like the one found in Shenzhen Liandian IP cameras.
  • Dark Web Monitoring Service: PurpleOps monitors underground forums and other dark web sources for discussions about exploits and vulnerabilities, providing early warning of potential attacks. Our telegram threat monitoring capabilities can also provide additional layers of security intelligence.
  • Breach Detection: We offer breach detection services that can identify and respond to unauthorized access attempts, helping to contain the impact of a successful attack.
  • Underground Forum Intelligence: Gain insights into threat actor discussions about exploits and vulnerabilities. This information can be invaluable in understanding the potential risks and preparing for potential attacks.
  • Brand Leak Alerting: Our services include alerts for any unauthorized exposure of your brand’s sensitive data. This allows organizations to rapidly respond to potential leaks and minimize damage.

By leveraging these services, organizations can improve their overall security posture and defend against vulnerabilities like CVE-2025-7503.
PurpleOps also provides services such as red team operations and penetration testing which can help to discover vulnerabilities such as this one within your own infrastructure.

Practical Implications

Technical Readers:

  • Implement Network Segmentation: Immediately isolate IP cameras on a separate VLAN to limit lateral movement in case of compromise.
  • Create Firewall Rules: Block all Telnet traffic to and from these devices to prevent exploitation.
  • Monitor Traffic: Set up network monitoring rules to detect unusual outbound connections or data transfers.
  • Update Firmware: If a patch becomes available, test it thoroughly in a lab environment before deploying it to production.

Non-Technical Readers:

  • Inventory Devices: Maintain a detailed inventory of all IoT devices on the network, including make, model, and firmware version.
  • Assess Risk: Understand the potential impact of a compromised device on your organization.
  • Communicate with IT: Work with your IT department to implement the necessary security controls.
  • Consider Replacements: If the risk is high and no patch is available, consider replacing vulnerable devices with more secure alternatives.

These actions can help organizations, regardless of their technical expertise, to manage the risks associated with IoT device vulnerabilities.

Conclusion

The CVE-2025-7503 vulnerability serves as a reminder of the risks associated with IoT devices and the importance of proactive security measures. By understanding the specifics of this flaw and implementing the recommended mitigation strategies, organizations can reduce their attack surface and protect their networks. PurpleOps can assist in this process by providing a comprehensive suite of cybersecurity services, including threat intelligence, supply-chain risk monitoring, and breach detection.

To learn more about how PurpleOps can help secure your organization against IoT vulnerabilities and other cyber threats, please visit our platform or contact us for more information.

FAQ

Q: What is CVE-2025-7503?
A: CVE-2025-7503 is a critical vulnerability in Shenzhen Liandian IP cameras that allows attackers to gain root access through an undocumented Telnet service.

Q: What is the CVSS score for this vulnerability?
A: The vulnerability has a CVSSv4 score of 10.0, indicating maximum severity.

Q: Is there a patch available for CVE-2025-7503?
A: No, the vendor has not released a patch or official advisory for this vulnerability.

Q: What can I do to mitigate this vulnerability?
A: Mitigation strategies include network segmentation, firewall rules, traffic monitoring, and device replacement.

Q: How can PurpleOps help?
A: PurpleOps offers cyber threat intelligence, supply-chain risk monitoring, and breach detection services to help organizations defend against vulnerabilities like CVE-2025-7503.