The Internet of Things (IoT) has become deeply embedded in our daily lives, powering everything from smart homes and wearable health monitors to industrial automation and critical infrastructure. As of 2025, over 17 billion IoT devices are connected globally, which is expected to surpass 25 billion within just a few years. While this hyperconnectivity brings tremendous convenience and efficiency, it also introduces a massive and rapidly expanding attack surface for cybercriminals.

Unfortunately, many IoT devices are rushed to market with little regard for security. Insecure firmware, outdated protocols, default passwords, and weak or absent encryption make them easy targets. This blog dives deep into the vulnerabilities plaguing IoT devices today, why they’re particularly susceptible to attacks, and what users and manufacturers can do to defend against evolving threats in 2025 and beyond.

What are IoT attacks?

IoT attacks target Internet of Things (IoT) devices, including smart home gadgets, wearable technology, connected appliances, industrial sensors, and more. These devices are often connected to the Internet and each other, making them convenient but also vulnerable to exploitation.

Unlike traditional cyberattacks on PCs or servers, IoT attacks often exploit the limited security of small, embedded devices. Attackers use weak passwords, outdated firmware, or insecure communication protocols to gain unauthorized access to, control over, or data from the device.

Understanding IoT Vulnerabilities

The rapid proliferation of Internet of Things (IoT) devices, from smart speakers and thermostats to industrial robots and medical equipment, has transformed how we live and work. But beneath the surface of this innovation lies a growing cybersecurity concern: IoT vulnerabilities. These are flaws or weaknesses in devices that hackers can exploit to gain unauthorized access, disrupt services, steal data, or launch broader attacks. As the number of connected devices rises, so does the scale and severity of these security threats.

A Growing Concern in 2024–2025

IoT vulnerabilities are more than just technical flaws; they are real threats with measurable consequences. In 2024 alone, global IoT-related cyberattacks rose by more than 124%, according to IBM X-Force and Fortinet’s threat intelligence reports. By 2025, an estimated one in every three cyber incidents involves at least one IoT device. Furthermore, over 60% of deployed IoT devices still operate on outdated or unpatched firmware, making them prime targets for attackers. This rapid escalation highlights how IoT security has become a top priority for organizations, regulators, and consumers.

Common Types of IoT Vulnerabilities

Default Credentials

Many IoT devices are shipped with factory-default usernames and passwords such as “admin” or “123456.” Shockingly, many users never change them, allowing attackers to easily access the device using automated tools that scan for standard logins.

Outdated Firmware

Manufacturers often fail to provide ongoing firmware updates, or users neglect to install them. As a result, known vulnerabilities remain unpatched, leaving devices open to exploitation for months or even years after discovery.

Unencrypted Communication

IoT devices transmit sensitive data (location, camera feeds, or usage logs) over unencrypted channels. Without encryption, attackers can intercept and alter this data during transmission.

Open or Unnecessary Ports

Some IoT devices expose unnecessary network ports for regular operation. If these ports are not adequately secured, they can be exploited to run malicious commands or gain administrative control over the device.

Insecure APIs

Application Programming Interfaces (APIs) connect IoT devices to cloud services or mobile apps. Poorly designed or inadequately protected APIs can allow attackers to bypass authentication, access sensitive data, or even take complete control of the device remotely.

Lack of Authentication

Some devices don’t require user authentication or rely on weak login mechanisms. In worst-case scenarios, attackers can gain access without needing credentials, especially on devices intended for plug-and-play use.

Hardcoded Backdoors and Keys

Manufacturers sometimes embed hardcoded credentials or “backdoors” to facilitate support or testing. If discovered by attackers, these hidden access points can be used to infiltrate systems undetected.

Real-World Examples of IoT Vulnerabilities

Mirai Botnet Resurgence (2023–2025)
Initially surfacing in 2016, the Mirai botnet made a significant comeback between 2023 and 2025, exploiting default credentials in millions of IoT devices. The infected devices were weaponized to launch massive DDoS (Distributed Denial of Service) attacks on public infrastructure and internet providers.

Ripple20 Vulnerabilities
Ripple20 refers to 19 security flaws in a widely used TCP/IP library embedded in various IoT devices, such as printers, medical infusion pumps, and industrial systems. Despite being discovered years ago, millions of devices remained unpatched in 2025, making them vulnerable to remote exploitation.

eSIM Backdoor Vulnerability (2025)
A critical flaw discovered in July 2025 allowed attackers to access eSIM-enabled devices through a “test mode” backdoor. This flaw, affecting over 2 billion smartphones and connected gadgets, enabled the installation of unauthorized applications and the interception of mobile data.

IoT Security Issues: Key Challenges in Securing a Connected World

The Internet of Things (IoT) has opened new doors for innovation and automation and created complex security challenges. IoT security issues are not isolated to device flaws; they span the entire ecosystem, including device design, data transmission, user behavior, cloud integration, and supply chain management. The following are the most pressing IoT security issues. 

Lack of Security-by-Design

Many IoT devices are built with functionality, speed to market, and cost-efficiency in mind, but not security. Manufacturers often ignore safeguards like secure boot processes, hardware-based encryption, and intrusion detection mechanisms. As a result, devices ship with exploitable vulnerabilities right out of the box.

Weak Authentication and Authorization

Many devices either lack strong password protection or fail to support multi-factor authentication. Some don’t even have user-access controls, allowing any network-connected device to access critical functions. Weak or default credentials are still a leading cause of IoT breaches, especially in consumer-grade devices.

Insecure Data Transmission

Many IoT devices, especially older or low-cost devices, transmit data without proper encryption. When data is sent over HTTP instead of HTTPS or lacks end-to-end encryption, it becomes susceptible to eavesdropping, tampering, or man-in-the-middle (MITM) attacks.

Infrequent or No Firmware Updates

Unlike smartphones or PCs, IoT devices often don’t receive timely security patches. Even when updates are available, users might not apply them due to a lack of awareness, manual update requirements, or fears of device disruption. This leaves known vulnerabilities unpatched for extended periods.

Exposure to the Internet

Many IoT devices are unnecessarily exposed to the public internet by design or misconfiguration. Devices with open ports and services can be discovered and exploited through tools like Shodan, allowing attackers to control them remotely or use them as entry points into larger networks.

Supply Chain Risks

IoT devices often rely on third-party hardware and software components from multiple vendors. A vulnerability in any part of this chain can be introduced unknowingly and exploited later. High-profile cases, like Ripple20 and the 2025 eSIM flaw, illustrate the risks embedded deep within the supply chain.

Major IoT Device Vulnerabilities

IoT vulnerabilities come in many forms, but some are more severe or widespread than others. Here are the most critical IoT device vulnerabilities identified across consumer, enterprise, and industrial sectors:

Default Credentials and Open Telnet/SSH Ports

Many IoT devices still ship with default usernames and passwords like “admin/admin” or “root/1234.” When these credentials are left unchanged, attackers can use automated scripts to gain access through open Telnet or SSH ports. This remains one of the easiest and most common attack vectors.

Buffer Overflow Exploits

In 2024, over 28% of IoT vulnerabilities reported were due to buffer overflow issues. In these flaws, attackers can execute malicious code by sending more data than the memory buffer can handle. These flaws have affected devices like routers, IP cameras, and smart hubs.

Denial of Service (DoS) Vulnerabilities

Over 27% of IoT exploits documented in 2024 were related to DoS vulnerabilities. By sending malformed packets or overloading device resources, attackers can crash devices, disrupt services, or create backdoors for further intrusion.

Insecure Firmware and Update Mechanisms

Many devices lack secure firmware validation processes. This allows attackers to replace the existing firmware with modified versions containing backdoors or malware. Some devices don’t even use encryption or code-signing to verify update authenticity.

Hardcoded Credentials and Backdoors

Vendors sometimes embed hidden usernames, passwords, or backdoor commands to make device testing easier. However, if these hardcoded credentials become public, anyone can gain access. The 2025 eSIM vulnerability exploited a backdoor, impacting over 2 billion devices.

Vulnerable APIs and Web Interfaces

IoT devices frequently use web interfaces or APIs to allow user interaction. If these interfaces are not secure, such as by sanitizing inputs or authenticating requests, they can be used to carry out cross-site scripting (XSS), remote code execution (RCE), or privilege escalation.

Why IoT Devices Are More Vulnerable?

Limited Security Features

IoT devices are often designed with minimal hardware and software, limiting their ability to support robust security measures. Unlike traditional computers, they typically lack the processing power to run complex encryption algorithms, firewalls, or antivirus software. This trade-off between performance and cost-efficiency exposes many IoT devices to basic cyberattacks.

Default and Hardcoded Credentials

Many IoT devices ship with default usernames and passwords such as “admin/admin” or “user/password.” Sometimes, these credentials are hardcoded and cannot be changed, making them easy targets for attackers. When users neglect to change these defaults, automated bots and malware can exploit devices on a large scale.

 Lack of Regular Updates and Patches

Manufacturers of IoT devices often fail to provide timely security updates or stop supporting devices shortly after release. This makes it difficult to patch vulnerabilities as new threats emerge. Even when updates are available, many IoT devices don’t have an automated update mechanism, relying on users to perform manual updates that are often overlooked.

Large Attack Surface

IoT ecosystems involve a vast network of interconnected devices, sensors, cloud services, and mobile applications. Each connection point increases the overall attack surface. If one device is compromised, it can provide a pathway to infiltrate the entire system.

Physical Accessibility

Many IoT devices are deployed in physically accessible locations, such as smart doorbells, home routers, or industrial sensors. Attackers with physical access can tamper with the hardware or retrieve sensitive data directly from memory, bypassing network-based defenses.

Common IoT Attack Methods and Techniques

1. Botnet Attacks

One infamous attack vector is hijacking IoT devices to form botnets. These botnets, like Mirai, are used to launch Distributed Denial-of-Service (DDoS) attacks. By exploiting weak credentials and open ports, attackers gain control over thousands of devices to flood targeted servers with traffic, causing outages and disruptions.

2. Man-in-the-Middle (MitM) Attacks

In a MitM attack, an attacker intercepts communication between an IoT device and its server or another device. If communication is not properly encrypted, sensitive data such as login credentials, health records, or camera feeds can be captured and manipulated without the user’s knowledge.

3. Firmware Exploitation

Attackers often exploit vulnerabilities in outdated or poorly secured firmware. They can gain persistent control over a device by injecting malicious code into the firmware. This attack can sometimes permanently “brick” a device or turn it into a surveillance tool.

4. Side-Channel Attacks

These attacks exploit the physical characteristics of IoT devices such as power consumption, electromagnetic emissions, or timing information to extract sensitive data like cryptographic keys. Although technically complex, side-channel attacks can be particularly effective on low-cost devices without protection against such threats.

5. Data Eavesdropping

IoT devices constantly collect and transmit data, often without encryption. This makes it easy for attackers to intercept sensitive information during transmission. For example, smart home devices may leak data about user behavior, routines, and personal preferences, which can be valuable for targeted phishing or identity theft.

6. Rogue Device Insertion

In this method, attackers introduce unauthorized devices into the IoT network. These rogue devices can impersonate legitimate ones, collect data, or disrupt normal operations. Such attacks can lead to operational failures or safety hazards in industrial settings.

7. Privilege Escalation

Once an attacker gains initial access to an IoT device, they may exploit software bugs to escalate privileges and gain administrative control. From there, they can change configurations, disable security features, or pivot to other network parts.

Signs Your IoT Device Has Been Attacked

1. Unusual Device Behavior

Strange behavior is one of the most apparent signs of a compromised IoT device. This can include lights blinking without reason, devices turning on or off by themselves, or changes in settings that you didn’t make. If a smart thermostat adjusts temperatures randomly or a security camera pans and tilts unexpectedly, it could indicate unauthorized access or malicious control.

2. Unexplained Data Usage or Bandwidth Spikes

Many IoT attacks involve devices sending or receiving large amounts of data. Suppose you notice a sudden spike in your internet bandwidth or unexpected data usage, especially from devices that typically use little bandwidth. In that case, it may mean the device is part of a botnet or transmitting stolen data to an external server.

3. Sluggish Network Performance

Compromised IoT devices can slow down your home or business network. This happens because infected devices might be used to perform background tasks such as spamming, scanning, or DDoS attacks. If your network becomes unusually slow and you’ve ruled out other causes, check your IoT devices for signs of compromise.

4. Device Becomes Unresponsive or Crashes Frequently

A hacked IoT device may freeze, crash, or fail to respond to commands. Malware or unauthorized control scripts can overload the device’s processor or memory, leading to instability. If your device is constantly rebooting or lagging, it might be under the control of a malicious actor.

5. Unauthorized Account Access or Changes

Some IoT devices are linked to mobile apps or online accounts. If you receive alerts about logins from unfamiliar locations, or if settings and passwords are changed without your knowledge, it’s a strong indicator that someone has gained unauthorized access.

6. Unrecognized Devices on Your Network

Regularly monitoring your Wi-Fi network can reveal unfamiliar devices connected to it. If you find a device with a suspicious name or MAC address you didn’t authorize, it could mean an attacker has planted a rogue device or is spoofing an existing one to intercept communications.

7. Increased Power Consumption

A sudden increase in electricity usage by an IoT device can indicate that it’s running unauthorized processes in the background. For example, a hacked smart plug or camera might be transmitting data or mining cryptocurrency without your consent.

8. Security Alerts or Warnings

Modern routers or security systems can detect unusual traffic or behavior from connected devices. If you receive warnings about suspicious activity, such as outbound connections to unknown IP addresses, it may mean one or more of your IoT devices have been compromised.

How Does a VPN for IoT Secure Your Devices?

A VPN for IoT secures your devices by creating an encrypted tunnel between them and the internet, protecting all data in transit from being intercepted or tampered with. This is especially important for IoT devices that often lack built-in security features. By encrypting communication, AstrillVPN shields sensitive data such as video feeds, location data, or health information from hackers or eavesdroppers. It also masks the device’s IP address, making it harder for cybercriminals to identify or target it directly, especially when scanning networks for vulnerabilities.

In addition to encryption and anonymity, AstrillVPN allows IoT devices to safely connect over public or unsecured networks without exposing themselves to local threats. It helps prevent common attacks like man-in-the-middle breaches, botnet recruitment, and unauthorized access. For businesses, a VPN also provides secure remote access to industrial IoT systems, ensuring that only verified users can interact with critical infrastructure. 

How to Protect Your IoT Devices?

1. Change Default Credentials Immediately

Changing the default usernames and passwords is one of the first and most essential steps to secure your IoT devices. Manufacturers often ship devices with simple, well-known credentials like “admin” or “1234,” which hackers can easily exploit. Always create strong, unique passwords for each device, and if supported, enable two-factor authentication to add an extra layer of protection.

2. Keep Firmware and Software Updated

Regularly updating your IoT devices ensures they have the latest security patches and bug fixes. Many attacks exploit known vulnerabilities in outdated firmware. Check the manufacturer’s website or app for updates, and if possible, enable automatic updates. Devices no longer supported by the manufacturer should be replaced, as they pose a continuous security risk.

3. Secure Your Home or Office Network

A strong and secure Wi-Fi network forms the foundation of IoT security. Use a complex password for your Wi-Fi and enable WPA3 or WPA2 encryption. It’s also recommended to create a separate guest or dedicated IoT network, isolating your smart devices from your main devices like laptops and phones. This way, even if an IoT device is compromised, the attacker won’t gain easy access to more critical systems.

4. Use a VPN or Firewall for Added Protection

A Virtual Private Network can encrypt traffic from your IoT devices, protecting the data they send and receive. This is especially useful for devices that access the internet frequently, such as security cameras or intelligent assistants. Additionally, a network firewall or intrusion detection system can monitor traffic and block malicious access attempts before they reach your devices.

5. Disable Unused Features and Services

Many IoT devices have features like remote access, voice assistants, or location tracking enabled by default. If you don’t use these services, it’s best to disable them to reduce the attack surface. Limiting device functionality to only what you need helps minimize the potential entry points for hackers.

6. Monitor for Unusual Activity

Watch for strange behavior such as unexpected device reboots, altered settings, or high data usage. These may be signs that your device has been compromised. Use apps or network management tools to track your devices, check for unfamiliar connections, and review logs regularly.

Conclusion

As IoT devices become more widespread in daily life and critical systems, securing them is more important than ever. Understanding the risks, recognizing signs of compromise, and implementing basic security measures can significantly reduce vulnerabilities. With proactive steps, users and organizations can enjoy the benefits of IoT without compromising safety or privacy.

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