ever you find strange timestamp on file metadata? it may manipulated with program called touch where you can change timestamp whatever you want.
touch [-acm] [-r ref_file|-t time|-d date_time] file...so eventually you want to make a change to file obviously without leaving suspicious to file owner, you should try this one that will make people unconscious, in that case where this method was actually dangerous that manipulating timestamp might make we don’t know when we got hacked system which file has been changed.
# Example which change access (a option parameter) and modification (m option parameter) to current time (time parameter leaved blank)
touch -am frayed.file
# Manipulate based on reference File
touch -r reference.file victim.file
# Manipulate based on reference with Backward (in Seconds)
touch -r reference.file -B 3600 victim.file
# Manipulate Access time with String as [[CC]YY]MMDDhhmm[.ss]
touch -d "19 February 2010 10:30" frayed.file
touch -t "10:30" frayed.file
# Dump Timestamp Metadata
stat frayed.filewell, interesting huh? i think you should try it and back to the future.