What is UPnP? Why Is It Still a Security Risk?

Written by Hatice Ozsahan and David Worthington on July 25, 2023

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In a bustling tech union, similar to a regional organization, various tech companies collaborate to tackle common challenges. Each company represents a unique gadget, software, or tech service, creating a tight-knit community.

In this vibrant tech union, UPnP, a remarkable tech communicator, plays a crucial role as a superpower enabling seamless communication among all members. UPnP service works like magic, helping each gadget connect one another, share ideas, and cooperate effectively. It fosters unity as members work together towards common goals, just like a strong regional organization.

UPnP, however, cannot screen or select new members for the tech union, raising security concerns. Without a robust filtering mechanism, malicious actors could infiltrate undetected, exploiting UPnP’s open communication channels for harmful purposes.

We will now examine UPnP’s workings, discovering what it is, how it operates, why understanding past cyberattacks is essential before enabling UPnP ruthlessly, and answering the question of “Is UPnP still dangerous in 2023 and how do I mitigate the risks?”

What is UPnP?

UPnP, which stands for Universal Plug and Play, is a service that enables devices on the same local network to discover and connect with each other. It uses internet and web protocols like TCP/IP, HTTP, and DHCP to make devices familiar with each other, allowing them to work harmoniously.

UPnP’s convenience is undeniable, as it is fast, easy, and practical for users, often being used without them even realizing it. However, this convenience can also create a potential vulnerability, providing an open door for malicious hackers to exploit, leading to cyberattacks. Before exploring the threats and cyberattacks related to UPnP, let’s first understand how this system operates.

What Does UPnP Do?

UPnP is designed to make users’ lives more efficient and convenient by enabling devices to connect and interact seamlessly. It all starts when a device joins a network:

  • Discovery: When a device joins a network, it sends out a “discovery” message to find other devices that also support UPnP. It’s like waving hello to the other devices, saying, “Hey, I’m here, and I can speak UPnP too!” UPnP leverages port 1900 for this discovery phase. The device broadcasts its “discovery” message to all devices on the network using port 1900. This ensures that the message reaches every potential UPnP-enabled device in the vicinity.
  • Announcement: As devices receive the “discovery” messages through port 1900, those that support UPnP respond with their own “announcement.” This response is like friendly replies, telling the newcomer, “Hello! I’m here too, and I also speak UPnP!”
  • Description: After their first touch, each device provides a “description” of itself, the description includes their functions, capabilities and services in detail. For example, a smart tv might describe its display and streaming capabilities, while a printer would outline printing services.
  • Connection: Once the devices know about each other’s features, UPnP sets up the necessary connections for them to share data and control each other. For instance, your smart TV can effortlessly display photos from your smartphone, and your smartphone can remotely control the TV’s volume or playback.
  • Notifications: After being connected, devices sends UPnP notifications to each other of changes or events. For example, if your printer runs out of paper, it can send a UPnP notification to your computer, letting you know that it needs a paper refill.
  • Adaptability: Another remarkable aspect of UPnP is its ability to adapt to changes in the network. If a new device joins or an existing one leaves, UPnP ensures that all devices are aware of these changes and updates their configurations accordingly.

UPnP’s simplicity, speed, and efficiency enable seamless communication and cooperation among devices, providing users with a remarkably convenient experience.

UPnP Use Cases

As technology evolves and the desire to connect different devices grows, UPnP plays a vital role in achieving seamless device interactions within a local network. Some use cases of UPnP service include:

  • Home Automation: UPnP allows different smart home devices to communicate and work together seamlessly. In a smart home environment, for instance, one can use UPnP to make your smart thermostat communicate with your smart lighting system, allowing automatic lighting adjustments based on temperature changes.
  • Gaming: UPnP service simplifies networked gaming experiences by allowing gaming consoles and devices to discover and connect with each other effortlessly. Gamers can easily join multiplayer sessions, communicate in real-time, and share in-game content without dealing with complicated network settings.
  • Media Streaming: UPnP service is widely used for media streaming within a local network. The UPnP service allows streaming videos, music, and photos between UPnP-enabled devices, such as computers, without the need for complex configurations or additional software. It allows seamless multimedia sharing and playback across devices.
  • Remote Device Control: UPnP supports remote control of UPnP-enabled devices from a smartphone or computer. A smartphone can serve as a remote control for UPnP-enabled smart TVs or media players. This provides convenient access and control over devices from anywhere within the network.

UPnP’s versatility enhances user experiences by enabling smooth collaboration among various devices within a local network.

Why is UPnP Still a Security Risk?

Universal Plug and Play (UPnP) simplifies device interconnectivity. However, its security implications remain pertinent due to the inherent risks and potential for exploitation by malicious actors. Using UPnP may lead to a series of security hazards. Here we’ve gathered some malicious actions that may happen via using UPnP:

  • Malware Propagation: Malware and viruses can use UPnP to spread within a local network. If one device is infected, the malware could use UPnP to search for and infect other vulnerable devices on the network.
  • Unauthorized Access: UPnP may allow malicious actors to gain unauthorized access to devices on your local network. If a vulnerable UPnP-enabled device is discovered by an attacker, they could exploit it to gain control over the device, access sensitive data, or perform malicious actions.
  • Port Forwarding: UPnP can automatically set up port forwarding on the router to allow external access to devices within the local network. While this can be useful for certain applications, it can also inadvertently expose devices to the internet, making them potential targets for hacking attempts.
  • Data Leakage: UPnP facilitates data sharing among devices, but this may also introduce privacy risks if sensitive data is shared without proper authentication or encryption. Unauthorized devices gaining access to shared data could lead to data leakage or unauthorized disclosure.

Inherent Risks of UPnP

The risks associated with UPnP stem from its liberal and autonomous networking mechanism. Below are a few potential exploitation methods:

  • Creating gateways through firewalls by connecting internal ports to the router’s external side.
  • Exposing router web administration details through port forwarding.
  • Changing DNS server settings to load fraudulent websites instead of legitimate ones.
  • Modifying IP, WiFi, administrative credentials, and PPP settings.
  • Terminating or altering internal connections.

How Do Attackers Exploit UPnP?

Universal Plug and Play (UPnP) was designed to promote seamless networking experiences. However, the same functionality that allows devices to effortlessly communicate can also be a double-edged sword, creating potential security risks. Here, we delve into the specifics of how attackers exploit UPnP, transforming a protocol meant for convenience into a tool for malicious activities.

  • Port Forwarding Manipulation: UPnP’s primary functionality allows devices to set up port forwarding rules on a router automatically. Malicious actors can exploit this by programming malware to create port-forwarding rules on the router that redirect traffic to the attacker’s server. This makes it possible to launch attacks from inside your network, bypassing any inbound firewall rules you might have.
  • Firewall Penetration: UPnP can also be used to ‘poke holes’ in your firewall. By creating port forwarding rules, malware can expose vulnerable devices to the Internet, circumventing the protection usually offered by a firewall. This is especially problematic as many Internet of Things (IoT) devices have poor security and become easy targets once exposed.
  • Changing DNS Settings: UPnP has the potential to change DNS settings. By doing this, attackers can redirect all your web traffic through their server, allowing them to perform phishing attacks or steal sensitive information.
  • Device Control: Many smart devices in homes and businesses use UPnP for discovery and control. If these devices are not designed with strong security in mind, they can be taken over using UPnP to send harmful instructions.
  • DDoS Attacks: Distributed Denial of Service (DDoS) attacks can be amplified by exploiting UPnP. A small incoming signal can be reflected and amplified by UPnP devices, generating a massive amount of network traffic that can overwhelm target servers.

Examples of UPnP Cyberattacks

The potential security issues of Universal Plug and Play (UPnP) technology have been recognized for years, with multiple documented cases of UPnP exploitation in cyberattacks.

Flash UPnP Attack (2008)

The Flash UPnP attack occurs when a user interacts with a malicious SWF file (specially crafted Flash applet) on a web page, which then triggers a silent step attack in the background. The victim’s router forwards its ports, thereby exposing its connections to the entire internet. An enabled and updated firewall can provide some defense, but it’s not a guaranteed protection against Flash UPnP attacks.

Mirai Botnet Attack (2016)

In 2016, cybercriminals executed a colossal Denial-of-Service (DDoS) attack by compromising a network of IoT devices (mainly CCTV cameras) through UPnP technology. The magnitude of this cyberattack was so significant it caused an internet outage across much of the United States’ East Coast.

Pinkslipbot Attacks (Active since late 2000s)

The banking Trojan Pinkslipbot, also known as Qakbot and QBot, exploits UPnP to infect its victims. Infected machines are then used as HTTPS-based proxies to control servers and conceal the malicious activity being carried out. Pinkslipbot steals banking credentials from US financial institutions using man-in-browser attacks and password stealers.

CallStranger Vulnerability (Disclosed in 2020)

This newly disclosed vulnerability, known as CallStranger (CVE-2020-12695), affects billions of devices and can be exploited for a wide range of malicious activities, including DDoS attacks and data exfiltration. CallStranger is caused by a vulnerability in the UPnP SUBSCRIBE function, which can be manipulated by an attacker to trigger an SSRF-like vulnerability. Notably, it affects a vast range of devices from many manufacturers, including Windows PCs, gaming consoles, televisions, and routers.

Awareness of these notable cyberattacks provides a vital understanding of the potential dangers associated with UPnP technology. Regular updates, diligent monitoring of vulnerabilities, and adherence to the latest security specifications are key in mitigating these risks.

Should I Enable UPnP?

If your network primarily consists of devices that require UPnP for functionality, and you are willing to invest the necessary time to maintain a secure network (regular updates, patches, and robust security measures), enabling UPnP might be worth considering. However, if your security needs are high, or you prefer to have control over what changes are made to your network configuration, it would be safer to keep UPnP disabled. Always evaluate the trade-offs between convenience and security when making decisions regarding UPnP. 

Also, If you still want to go with UPnP enabled, don’t give in and go with the flow. There are still some security measures that will enhance your security posture while your UPnP is enabled. Don’t forget,  UPnP itself isn’t inherently dangerous, its misuse can lead to significant security breaches.

Safety Measures and Recommendations

To effectively manage and mitigate the inherent risks associated with the use of UPnP, consider implementing the following measures:

  • Routine System Updates: Regularly updating your entire network infrastructure, including routers, firewalls, antivirus software, and IoT devices, is crucial. This proactive approach ensures you’re up to date with the latest security patches, which helps shield your network from known vulnerabilities.
  • Active Vulnerability Monitoring: Stay vigilant about potential threats to your network by regularly consulting resources such as the National Institute of Standards and Technology’s (NIST) continuously updated list of Common Vulnerability Exposures (CVEs). This practice equips you with the necessary knowledge to identify, understand, and counter potential security risks.
  • Strict UPnP Specifications Adherence: If UPnP usage is non-negotiable due to specific requirements of your devices or network setup, ensure you adhere strictly to the updated UPnP security specifications provided by the Open Connectivity Foundation. By adhering to these guidelines, you’ll leverage the best practices in UPnP use, reducing your network’s vulnerability to potential exploitation.

UPnP service is a powerful technology that enables seamless communication and cooperation among devices within a local network. It has numerous use cases, ranging from home automation and gaming to media streaming and remote device control. However, the convenience it offers comes with inherent security risks. UPnP’s open nature can be exploited by malicious actors to propagate malware, gain unauthorized access, perform port forwarding manipulation, and engage in other cyberattacks.

To use UPnP safely and effectively, it is crucial to be aware of the potential risks and take proactive measures to mitigate them. This includes regularly updating network infrastructure and devices, monitoring vulnerabilities, and adhering strictly to UPnP security specifications.

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Hatice Ozsahan
David Worthington

I'm the JumpCloud Champion for Product, Security. JumpCloud and Microsoft certified, security analyst, a one-time tech journalist, and former IT director.

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