Scripting
Where this stands
No Sigma rule can address this — the telemetry MITRE names has no Sigma logsource behind it.
Sigma has no logsource taxonomy for ICS. MITRE's telemetry here is operational historians and controller state, which no Sigma rule can address.
What the technique is
Adversaries may use scripting languages to execute arbitrary code in the form of a pre-written script or in the form of user-supplied code to an interpreter. Scripting languages are programming languages that differ from compiled languages, in that scripting languages use an interpreter, instead of a compiler. These interpreters read and compile part of the source code just before it is executed, as opposed to compilers, which compile each and every line of code to an executable file. Scripting allows software developers to run their code on any system where the interpreter exists. This way, they can distribute one package, instead of precompiling executables for many different systems. Scripting languages, such as Python, have their interpreters shipped as a default with many Linux distributions. In addition to being a useful tool for developers and administrators, scripting language interpreters may be abused by the adversary to execute code in the target environment. Due to the nature of scripting languages, this allows for weaponized code to be deployed to a target easily, and leaves open the possibility of on-the-fly scripting to perform a task.
Read it on attack.mitre.orgWhat MITRE says you would watch
- AN1868
Monitor command-line arguments for script execution and subsequent behavior. Actions may be related to network and system information Discovery, Collection, or other scriptable post-compromise behaviors and could be used as indicators of detection leading back to the source script. Scripts are likely to perform actions with various effects on a system that may generate events, depending on the types of monitoring used. Monitor log files for process execution through command-line and scripting activities. This information can be useful in gaining additional insight to adversaries' actions through how they use native processes or custom tools. […]
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