This binary can be downloaded along side multiple software downloads on the microsoft website. It gets downloaded when the user forgets to uncheck the option to set Bing as the default search provider.
checkymander - @checkymander
DefaultPack.EXE spawned an unknown process
Usecase:Can be used to execute stagers, binaries, and other malicious commands.
DefaultPack.EXE /C:"process.exe args"