has registered algorithmically generated Twitter handles that are used for C2 by malware such as .  has also used legitimate web services such as Dropbox and Constant Contact in their operations.(Citation: FireEye APT29)
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 registered algorithmically generated Twitter handles that are used for C2 by malware such as .  has also used legitimate web services such as Dropbox and Constant Contact in their operations.(Citation: FireEye APT29) ### Response: T1583.006.