1. For the first time, Mac users are feeling the threat of ransomware thanks to the "KeRanger" malware, which researchers spotted on Friday.
2. Adobe will release patches on Tuesday for vulnerabilities in Reader and Acrobat.
3. A Turkish hacker who spearheaded an ATM fraud ring pleaded guilty in the United States.
4. With tax season in full swing, be wary of spear phishing emails capitalizing on refund ruses.
5. Ray Tomlinson, the inventor of email as we know it, passed away.