Conditional Compilation
For use with DEFINE for more configurable and efficient payloads
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For use with DEFINE for more configurable and efficient payloads
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As covered in the , DEFINE can be used to declare constants used throughout your payloads. Using DEFINE and some additional commands described below we can gain even more control over the source code that get included into your inject.binduring compilation.
Imagine you have a payload that you would like to add some optional features to. With the help of a DEFINE you could provide a set of boolean constants to toggle those features on or off; consider the example below:
Here we have #EnableExtraFeature1 set to TRUE. At the time of compile IF #EnableExtraFeature1 THEN will become IF TRUE THEN which will allow for the code within that IF statement to be executed.
While the payload user is deciding to enable that feature before compiling their inject.bin by setting #EnableExtraFeature1 to TRUE, the USB Rubber Ducky is still evaluating the IF statement during runtime of the payload even though we know IF TRUE will always evaluate to TRUE.
In the opposite case, the features that are disabled are still compiled into the inject.bin . The USB Rubber Ducky still has to evaluate the IF #EnabledExtraFeature3 THEN which we know will become IF FALSE THEN to decide to skip the code within the IF statement. This becomes not only a waste of space but a waste of computation that could be better used.
Using IF_DEFINED_TRUE IF_NOT_DEFINED_TRUE and ELSE_DEFINED,we can conditionally include portions of our payload in the resulting inject.bin.
With IF_DEFINED_TRUE, the code within it's body/block will be compiled into the inject.bin ONLY if the given LABEL exists and evaluates to TRUE
As the opposite of IF_DEFINED_TRUE, with IF_NOT_DEFINED_TRUE, the code within it's body/block will be compiled into the inject.bin if the given LABEL does not exist or evaluates to FALSE
Used in combination with IF_DEFINED_TRUE and IF_NOT_DEFINED_TRUE to provide the alternative to the provided condition; the negated case. Code within the ELSE_DEFINED body/block will only be included if the paired IF_DEFINED_TRUE or IF_NOT_DEFINED_TRUE case is not met.