has used  to change file extensions to their true type that were masquerading as .txt files. 
Below is an instruction that describes a task, paired with an input that provides further context. Write a response that appropriately completes the request. ### Instruction: List the MITRE techniques contained in the text. ### Input: has used  to change file extensions to their true type that were masquerading as .txt files.  ### Response: T1036.