What Is a Sandbox?

In the world of cybersecurity, a sandbox environment is an isolated virtual machine in which potentially unsafe software code can execute without affecting network resources or local applications. Think of a sandbox as a controlled playground where applications, code, and files can be tested or executed to see how they behave. If the software behaves maliciously or unexpectedly, it doesn’t have the power to affect anything outside of that contained environment.

The term “sandbox” is aptly derived from the concept of a child’s sandbox—a play area where kids can build, destroy, and experiment without causing any real-world damage. Similarly, a digital sandbox allows experimentation and testing without repercussions outside its confined space.

Cybersecurity researchers use sandboxes to run suspicious code from unknown attachments and URLs and observe its behaviour. Telltale signs include whether the code replicates itself, tries to contact a command-and-control server, downloads additional software, encrypts sensitive data, etc. Because the sandbox is an emulated environment with no access to the network, data or other applications, security teams can safely “detonate” the code to determine how it works and whether it’s malicious.

Developers also use sandbox testing environments outside of cybersecurity to run code before widespread deployment.

In a standard business production environment, a sandbox might be misunderstood or considered a needless expense. But sandboxes are critical for several scenarios in development, cybersecurity and research. Ensuring the sandbox is truly isolated and secure is more important for cybersecurity research than software development because malware actively and aggressively scans the network for exploitable vulnerabilities.

Sandboxing in Development

In development, sandboxing usually involves a development server and a staging server. The development server is separated from the production environment but may need basic network access. Developers use sandboxes to test new software or updates. It ensures that any potential bugs, errors, or issues in the latest software don’t affect the stable running versions. It also prevents unintentional security vulnerabilities from being exploited.

The staging server is a replica of production where quality assurance (QA) tests code before deploying to production. Because the staging environment is the same as the production environment, code that runs without issues in staging should run seamlessly in production. After the code is tested, it’s deployed to production.

Sandboxing in Cybersecurity Research

Cybersecurity researchers and analysts use their sandbox environment in a similar way. But in this case, ensuring network resources are not susceptible to malware is much more critical. The sandbox environment has its own network and typically doesn’t have a physical connection to production resources. The purpose of the sandbox is to execute malicious code and analyse it. Sometimes, this code could be a zero-day exploit where the malware’s effect and payload are unknown. Because of this, the sandbox must not have access to critical infrastructure.

With a sandbox, cybersecurity researchers and analysts can understand how malware works and how to stop it. It’s the first step in designing antivirus software to prevent malware from spreading to other systems and to remove it from the already-infected systems. The overarching purpose is to provide a secure environment to run potentially harmful or untrusted software. Other objectives include:

• Network Protection: Sandboxes are often integrated with network protection tools. Emails, downloads, and other incoming files can be automatically routed through the sandbox to check for malicious behaviour before they reach the end-user.
• Forensic Analysis: After a cyber-incident, cybersecurity experts use sandboxes to understand the depth and impact of the attack. This enables them to dissect malicious payloads to analyse their origins, behaviours, and potential spread to inform incident response and recovery.
• Application Compatibility: Organisations migrating to new systems or platforms can use a sandbox to test how legacy applications or data perform, ensuring no compatibility issues.
• Regulation and Policy Compliance: Certain industries have stringent regulations about data security, integrity, and access. Sandboxes aid in validating and ensuring that software and processes comply with such regulations without risking data breaches.
• Learning and Experimentation: Educational institutions and individuals learning about cybersecurity often use sandboxes as training grounds. Sandboxing offers a safe environment for students to understand cyber-attack techniques, vulnerabilities, and defence mechanisms without posing risks to actual systems.

For complex attacks, sandbox environments are readily available to quickly analyse and stop malware before it becomes a global issue. Ransomware, for example, can spread globally and crash critical government systems. That’s why researchers must have ready access to sandboxes to help stop it.

What’s being tested determines how sandboxing functions. For instance, a sandbox environment used to test malware functions differently from a sandbox that tests code for application updates. For research into potential malware and execution of malicious code, a sandbox requires isolation from production software.

Regardless of how a sandbox is used, every environment operates using a similar set of functions:

• Device Emulation: Sandboxes emulate real-world devices, whether desktop, mobile, or other computing devices. The goal is to make the test software believe it’s interacting with real hardware, including simulated resources such as CPU, memory, and storage.
• Operating System Emulation: The sandbox emulates the target operating system. Through virtual machines, this emulated environment mimics the specific OS the software expects to interact with, ensuring accurate testing conditions.
• Virtualised Environment: Typically housed on a virtual machine, a sandbox is shielded from direct interaction with physical hardware. This virtual environment, often termed a “jail”, restricts the software’s access to specific resources, ensuring its confinement.
• Detailed Monitoring: All its activities and interactions are tracked when testers execute software within the sandbox. This includes file system modifications, network communication, and system calls, which provide a lens to its true behaviour.
• Detecting Evasive Malware: Some advanced malware is designed to recognise when it’s in a sandbox and alter its behaviour accordingly. It might look for signs of virtual environments or uncommon user interactions to remain undetected. If it senses it’s in a sandbox, the malware might lay dormant, revealing its true nature only in a real-world setting. Researchers continually optimise sandboxing environments to counteract these evasive tactics.
• Potential Exploits: Malware writers sometimes craft exploits targeting vulnerabilities in poorly secured sandboxes. This underscores the need for robust sandbox design and regular updates.
• Restricted Access: In many scenarios, sandboxes limit network access, ensuring the software cannot communicate freely with external servers or systems. Moreover, by controlling file system namespaces, sandboxes prevent unauthorised file modifications or accesses. Restricted access is also prevalent in cloud hosts and specific applications where sandboxes are employed to guarantee that the contained software can’t breach or compromise the host machine.

Think of sandboxing as an observatory where software is placed under a microscope. While it believes it’s operating in a natural computer environment, it’s confined to a controlled space, with its every move scrutinised for potential threats. This dynamic allows potential threats to be understood and countered before they can inflict real-world damage.

Sandboxing offers a myriad of advantages, from safeguarding data to promoting efficient software testing. Some of the most notable benefits of utilising a sandbox environment include:

• Enhanced Security: At its core, a sandbox provides an enhanced security layer. By keeping potentially harmful software within a controlled environment, sandboxing ensures broader systems and critical data remain untouched and uncompromised.
• Safe Testing Ground: Sandboxes serve as a development testing environment, enabling organisations to run applications in a secure space before they are introduced into the production stage. This safe space ensures that any damaging issues are addressed without compromising or slowing down critical resources.
• Email Quarantine: Sandboxes are commonly used as a quarantine zone for suspicious emails and their attachments. Email filters might flag potential threats, but administrators need a secure place to verify these without the risk of activation. In a sandbox, malicious attachments or macros, especially those targeting apps like Microsoft Office, can be scrutinised for safety.
• Proactive Threat Analysis: Sandboxes allow for proactive threat assessment and understanding, ensuring that organisations can detect and counteract potential risks before infiltrating the actual systems.
• Facilitates Software Testing: Beyond acting as a shield against threats, sandboxing is invaluable for developers. They can test new code, updates, or entire applications to identify and rectify issues without impacting the live environment.
• User-friendly for Employees: While sandboxes are invaluable tools for specialised cybersecurity personnel, their intuitive design ensures even employees without a tech background can utilise them. In turn, isolating and examining suspicious programmes ensure that individuals are running unknown codes without jeopardising primary systems.
• Cost-Efficient: Mitigating security breaches or addressing software glitches post-deployment can be costly. Sandboxing provides a preventive approach, which mitigates any financial and reputational expenses that organisations might otherwise face.
• Continuous Learning and Adaptation: The sandboxing environment provides an ongoing feedback loop. As it encounters threats and software behaviours, it helps update security protocols as needed.

In short, sandboxing allows organisations to ensure optimal software performance while maintaining robust security and ongoing innovation.

A sandbox can have both software and hardware components. With hardware restrictions, a sandbox could be on its own isolated network. For very restricted isolation, the sandbox could be on its own Wi-Fi router and ISP connection. This setup would make it physically impossible for a malicious application to access the main network.

Several applications use sandboxes by default to protect the local operating system. Browsers have their own sandboxes to separate malicious applications that run on the web from accessing local machine resources. Languages like Java have their own sandbox to protect local resources from untrusted code, such as a Java applet running on a web page.

The Windows 10 operating system has a built-in sandbox to protect the desktop from untrusted code. While this feature is not a replacement for antivirus, firewall, and anti-malware programmes, it adds a layer of security that older Windows operating systems do not have.

HTML5 has a sandbox to protect against misuse of its iframe feature. And the Linux operating system has several application sandboxes built on Seccomp and cgroup. Google Sandbox API is available to developers who write C++ code and need to sandbox their code before deploying it to the production environment.

Cloud-based sandboxes are virtual environments hosted in the cloud. They allow for the safe execution and analysis of code and provide scalability and flexibility for running multiple instances of sandboxes simultaneously.

Lastly, development environments are commonly constructed as a sandbox. Platforms like Docker and Kubernetes use containerisation, a type of lightweight sandboxing that allows developers to package an application with all its dependencies into a “container”. This ensures the application will run consistently across different environments.

A sandbox’s purpose depends on how you set it up. Many cloud platforms have their own sandbox to work with new programmes and updates. For instance, if you decide to work with PayPal as a payment processor, the platform has a full sandbox where you can emulate the production environment. Any code using the sandbox is isolated from production, so errors and bugs don’t affect the main platform.

If you need a sandbox to test code or potential malware, you can create your own sandbox by installing a virtual machine. VirtualBox is often used to host the virtual environment, also called a “virtual machine”. Then, you just need an installation file to run the operating system within the virtual machine.

Before installing the operating system within the virtual machine, set the hardware resources available to the environment, such as memory, CPU, storage capacity, and network adapter. These resources are virtualised and will be unavailable outside of the virtual machine. Conversely, programmes running in your new environment cannot share memory resources with the main operating system or anything outside of the virtual machine.

Even though a sandbox should be a safe space, attackers always try to break sandbox security. Technology firms typically offer large bounties to anyone who discovers a flaw in a sandbox that can be exploited. Microsoft Edge developers will pay up to $30,000 to anyone who can find a bypass on the browser’s sandbox. Google Chrome developers paid $60,000 to someone who executed unsanctioned code on a fully patched machine in 2012.

A sandbox is a must for security research or malware analysis. It ensures that all resources, including network storage, are unavailable to the virtual machine. With a sandbox, you can analyse code without the risk of destroying a production environment.

Proofpoint’s Targeted Attack Protection (TAP) solution utilises sandboxing as part of its cybersecurity approach. The sandboxing feature in TAP allows for the study and analysis of a wide variety of attacks, including those involving malicious attachments and URLs that can install malware or deceive users into sharing sensitive information.

By leveraging sandboxing, TAP creates a safe and isolated environment where potentially malicious programmes or unsafe code can be executed and observed without compromising the host devices or operating systems. This enables proactive detection and mitigation of advanced threats by analysing code behaviour and output activity within the sandbox.

Proofpoint’s TAP solution uses sandboxing as part of its overall Zero-Day Protection capability, which helps prevent potential threats from infiltrating the network and causing harm. This feature plays a crucial role in identifying and removing threats proactively, enhancing the organisation’s security posture.

In addition to sandboxing, Proofpoint’s TAP solution incorporates other security measures such as scanning, filtering, and predictive analysis to identify and mitigate advanced threats. The solution maintains a comprehensive information security programme aligned with industry standards, including encryption of data in transit and at rest, access control mechanisms, and vulnerability management.

To learn more, contact Proofpoint for more information.