Is a fake Coinbase transaction a scam?

In recent days, the cryptosphere has been abuzz with questions regarding the authenticity of Coinbase transactions. Could you elaborate on the nature of a potential fake Coinbase transaction and whether it constitutes a scam? Are there specific indicators that investors should be aware of to safeguard their digital assets? Furthermore, what measures does Coinbase take to protect its users from such fraudulent activities? And lastly, how can investors ensure that their transactions on Coinbase are secure and legitimate? Your insights into this matter would be greatly appreciated.