A Malware sandbox is a cybersecurity term referring to a specially prepared monitoring environment that mimics an end-user operating environment. Sandboxes represent an important tool in the arsenal of computer security experts and are used in conjunction with dynamic malware analysis techniques to safely observe the behavior of suspected malware in a controlled environment without risking a host machine.
Sandbox environments can be employed in a variety of configurations, depending on the needs of security researchers. Sandboxes can be virtual machine-based, an emulation of an end user’s operating system, or they can be full system emulations that simulate a host system’s physical hardware and operating system.
The use of sandboxes has increased in recent years as security experts grapple with increasingly innovative and evasive malware. Sandboxing is particularly effective as it is a proactive approach and offers high threat detection rates without risking a host machine. Sandboxes are also particularly effective at defending against new cybersecurity threats (also known as zero-day threats) that easily evade signature-based detection methods (which rely on previously categorized profiles to identify threats).
While malware sandboxes are a particularly effective cybersecurity tool, they can be time-consuming to deploy, and are still vulnerable to certain evasion techniques. There are three primary sandbox evasion techniques that malware employs to circumvent malware sandbox environments.
Relying on innate differences between sandbox environments and real systems, this evasion technique includes malware that actively searches for telltale signs or “artifacts” within the environment that may suggest it’s being run in a sandbox. These artifacts may be common virtual machine vendor names on files, the presence of monitoring hooks, or even unusual system compositions.
Context-aware malware refers to malware specimens that use time, event, or environment-based triggers to avoid detection, and has a situational awareness component that enables it to wait for an opportune moment before launching its attack.
Some malware attempts to take advantage of shortcomings in sandbox technology either by circumventing or removing the code segments and hooks used to monitor the sandbox environment itself. This sabotage can then create blind spots where the malware is safe to execute malicious code without being observed. Malware may also use old or obsolete file formats, taking advantage of sandboxes that don’t support these file formats in order to remain undetected.