Description

This is a more advanced version of the simpler gzip backdoor.

For this to be triggered:

a) the file must be a “concatenated gzip” b) this set of equations must be solved and the correct metadata written to the second gzip stream:

if (Math.pow(compressionLevel, operatingSystem) == parameters.getModificationTime() &&
        Math.pow(operatingSystem, compressionLevel) == 841L) ...