What Is UPnP and Why Is It a Security Risk?
Universal Plug and Play (UPnP) is a set of networking protocols that allows devices on the same local network to discover one another and establish seamless communication. It automates tasks like opening internal ports on routers, assigning IP addresses, and setting up service discovery for devices like smart TVs, printers, IP cameras, and gaming consoles.
Originally designed for convenience and rapid deployment in home environments, UPnP has found its way into enterprise networks—often without deliberate planning or oversight. This auto-configuration ability, while useful for consumers, creates significant exposure in business settings where unauthorized port openings or unverified device communications can bypass traditional controls. Environments with UPnP enabled often suffer from inconsistent configurations and hidden risk.
How UPnP Works—and Why It’s Dangerous
UPnP functions using protocols like SSDP (Simple Service Discovery Protocol) and HTTP. When a new device connects to the network, it sends a multicast discovery message over port 1900 UDP. Nearby UPnP-enabled devices respond with their capabilities and instructions for automatic configuration.
This automation introduces major risks:
- No authentication: UPnP assumes all devices are trusted and does not require credentials.
- External exposure: Many routers expose UPnP services to the internet due to misconfiguration.
- Silent port forwarding: UPnP can open firewall or NAT ports without alerting administrators.
- No access control: Any internal device can potentially send UPnP commands.
These flaws allow attackers to reroute traffic, expose services, and bypass segmentation—all without needing privileged credentials. Flash UPnP attacks have exploited these conditions, using malicious SWF files to open up ports to the internet.
What are Examples of Exploits and Vulnerabilities Related to UPnP?
Numerous attacks have taken advantage of UPnP weaknesses:
- Mirai Botnet: Compromised IoT devices via exposed UPnP ports, launching one of the largest DDoS attacks in history.
- EternalSilence: A set of UPnP vulnerabilities that enabled code execution on thousands of routers.
- Flash UPnP attacks: Malicious files on websites can send UPnP commands, causing a target’s routers to open ports to the internet.
- NAT traversal exploits: Used to expose internal applications or bypass internal firewall rules.
Security researchers have identified thousands of routers and appliances with UPnP exposed to the public internet—many of which had never been patched. Attackers connecting internal ports or injecting commands through the UPnP subscribe function gain remote device control with minimal effort.
Why UPnP Is a Growing Enterprise Threat in 2025
The risks posed by UPnP have escalated due to changes in the IT landscape:
- IoT proliferation: Smart cameras, lighting systems, and appliances often ship with UPnP enabled.
- Remote work infrastructure: Employees’ home routers may expose internal traffic via UPnP.
- Shadow IT: Bring Your Own Device (BYOD) policies and rogue device deployments can introduce UPnP-enabled systems without visibility.
- Third-party integration: Vendors or contractors may bring hardware that includes UPnP services.
These trends make UPnP a significant third-party and supply chain threat—not just an internal risk. Devices on the same local network often have unrestricted access to UPnP services, which increases risk.
How to Detect UPnP in Your Environment Detection starts with network visibility. Recommended tactics include:
- Network scanning: Use Nmap with the –script upnp-info flag to detect UPnP services.
- Log inspection: Review firewall and IDS logs for traffic to port 1900 UDP.
- SSDP traffic analysis: Look for multicast announcements or device responses.
- UPnP Inspector: Use dedicated UPnP discovery tools to map active endpoints.
- External attack surface scans: Identify exposed services on internet-facing assets.
Additional risk emerges from outdated firmware and unchanged DNS server settings. Changing DNS server settings and isolating UPnP-enabled devices is essential to maintaining control.
Steps to Disable or Secure UPnP Disabling UPnP at the perimeter is one of the most effective risk reduction steps. Recommendations include:
- Disable UPnP on all routers, gateways, and firewalls
- Block inbound and outbound SSDP traffic at the network edge
- Segment IoT or legacy devices onto isolated VLANs
- Use ACLs to restrict device discovery and communication
- Require vendors to certify UPnP is disabled by default
- Monitor for NAT port mappings and log all UPnP-related traffic
In rare cases where UPnP is needed for legacy support, limit access via network segmentation and endpoint controls. Enable UPnP only under strict governance and verify with updated UPnP security specifications.
UPnP and Third-Party Risk
Vendors and partners may unknowingly use hardware or software with UPnP enabled. This poses indirect risk to your network and can allow threat actors to access sensitive data through lateral movement.
Security leaders should:
- Ask about UPnP in vendor risk assessments
- Scan assigned vendor IPs for exposed SSDP services
- Require suppliers to follow secure configuration guidelines
- Use continuous external monitoring to detect protocol misuse
Frequently Asked Questions
Why is UPnP dangerous for enterprise use? UPnP allows devices to silently open ports and forward traffic without authentication—bypassing traditional security controls and enabling external access to internal connections.
Can UPnP be exploited remotely? Yes, especially if routers expose UPnP services to the internet. Some attacks can traverse NAT and expose internal systems.
Final Thoughts: Disable What You Don’t Control
UPnP was created for a simpler, more trusted network environment. Today’s networks are anything but. With threats exploiting legacy protocols, IoT bloat, and third-party access, UPnP is a liability.
Organizations that proactively disable or tightly control UPnP can reduce lateral movement risk, close shadow IT gaps, and defend more effectively against supply chain compromise.
Protect Your Supply Chain with Real-Time Threat Detection SecurityScorecard’s SCDR solution offers continuous monitoring of your third-party ecosystem, enabling swift identification and mitigation of cyber threats. Gain real-time visibility into legacy protocols like UPnP and respond before they expose critical assets.
