So one is often told on the basis of statements in the books of Deuteronomy and Joshua, the latter of which is said to describe an actual policy of extermination carried out by the Israelites against the non-Israelite inhabitants of Canaan. But both claims, argues Reuven Kimelman, rest on selective or inaccurate readings:
The popular reading of the [Israelites’ behavior toward the] Canaanites filters it through the prism of Deuteronomy. . . . In actuality, the biblical data are much more ambiguous [than generally assumed], making the most destructive comments the exception, not the rule. . . . With regard to the extermination of the seven nations of Canaan . . . the biblical record is . . . not of one cloth. The clarification of their status in the Bible requires a systematic treatment of all the data book by book. . . . Exodus’ position on the elimination of the Canaanites is a gradual dispossession by God, not by the Israelites.
Read more on Seforim: http://seforim.blogspot.com/2015/07/the-seven-nations-of-canaan.html