import re
rx = r"[^\s,=]+=\[[^][]*]"
s = "abc-1/1/0/E1 : name=abc-1/1/0/E1, kl/admin=up,kl/admin=up, kl/admin=[1, 2, 3]"
m = re.search(rx, s)
if m:
print( m.group() )
aW1wb3J0IHJlCnJ4ID0gciJbXlxzLD1dKz1cW1teXVtdKl0iCnMgPSAiYWJjLTEvMS8wL0UxIDogbmFtZT1hYmMtMS8xLzAvRTEsIGtsL2FkbWluPXVwLGtsL2FkbWluPXVwLCBrbC9hZG1pbj1bMSwgMiwgM10iCm0gPSByZS5zZWFyY2gocngsIHMpCmlmIG06CiAgcHJpbnQoIG0uZ3JvdXAoKSApCiAgICA=