In the recent second edition of his Jesus And The Eyewitnesses (Grand Rapids, Michigan: Eerdmans, 2017), Richard Bauckham addresses a popular objection to the traditional authorship attribution of the second gospel. Supposedly, the name Mark was common in the world of that day, which makes it more difficult for us to identify which Mark was being cited as the author. After presenting some of the evidence against that argument, Bauckham writes:
"So were there 'innumerable Marks' in the first-century Christian movement? If we exclude Roman citizens who had the name Marcus as their praenomen but would never have been known by this name alone, as the Mark to whom the Gospel is attributed clearly was, then there were probably only a few. Jewish Christians of this name would certainly have been very few. Among Jewish Christian leaders or teachers, such as could have written a Gospel or were likely to have a Gospel attributed to them, there may well have been only one Mark. This evidence about the rarity of the name Marcus among Jews also bears on the question whether the New Testament references are to three, two, or only one Mark. It is very likely that they are to only one." (541)
A post I wrote a couple of years ago discusses some of the evidence that the New Testament is referring to only one Mark. That post also discusses some of the evidence that Markan authorship of the gospel wouldn't have been fabricated. See here on gospel authorship more broadly.