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Loader interception

WHAT

An invasion, in the context of computer security, refers to unauthorized access or execution of code within a system. Runtime detection tools like Jibril are designed to identify and potentially block these unauthorized activities by monitoring system behavior at runtime. Jibril differentiates itself by intercepting all binary loads during the ELF (Executable and Linkable Format) loader time. This unique interception method allows it to analyze and manipulate the binaries before they are executed.

HOW

Jibril implements its functionality by placing hooks into both the kernel and the application space. Here’s a step-by-step breakdown of how this process typically works:

  1. Interception at ELF Loader Time: When an application attempts to load an ELF binary, Jibril intercepts this load before the binary is mapped into memory. This is crucial as it provides a preemptive check point.

  2. Binary Analysis: Upon interception, Jibril analyzes the binary for any signs of tampering or malicious content that could indicate an invasion attempt. This analysis might include checking for known signatures of malware, unusual entry points, or unexpected changes in the binary structure.

  3. Kernel and Application Hooks: By placing hooks in both kernel space and user space (the application), Jibril gains extensive visibility into how binaries interact with the operating system as well as how they behave during execution.

  4. Kernel Hooks: These allow Jibril to monitor system calls, file accesses, network operations, and other interactions with the OS that could be exploited by malicious binaries.

  5. Application Hooks: These are used to watch for abnormal application behavior such as unexpected process spawning, unusual memory access patterns, or other indicators of code injection or exploitation.

  6. Execution Control: Based on the analysis from steps 2 and 3, Jibril makes a decision whether to allow the binary to execute or not. If deemed safe, the ELF loader proceeds with mapping the binary into memory and executing it; if not, execution is blocked.

WHERE

The implementation of such a tool requires deep integration at multiple levels within a system:

  • ELF Loader: Modifications here are necessary for intercepting binary loads at their initial stage.
  • Operating System Kernel: Kernel modifications or extensions are required for placing hooks that monitor low-level system operations.
  • Application Space: Instrumentation within this layer is crucial for observing runtime behavior and interactions within running applications.

WHY

The primary reason for deploying such tools as Argos is to enhance security by preventing unauthorized code execution which can lead to data breaches, system damage, espionage, or other malicious outcomes:

  • Proactive Security Posture: By analyzing binaries before they execute and continuously monitoring behavior across both kernel and user spaces, tools like Argos can detect potential threats early in their lifecycle.
  • Comprehensive Coverage: The dual approach of hooking into both kernel and application layers ensures a more thorough observation capability across all aspects of system operation.
  • Control Over Execution: The ability to block execution based on pre-runtime analysis allows systems administrators and security professionals to prevent invasions before they can cause harm.

CONCLUSION

In summary, tools like Argos provide an essential defense mechanism against invasions by leveraging unique techniques for early detection through interception at ELF loader time combined with deep integration via hooks in both kernel and application spaces.