(Image credit: Getty Images) Ever since appearing on the cybersecurity scene, Nightmare-Eclipse (aka Chaotic-Eclipse) has probably been the largest thorn in the side of the Microsoft Security Response Center. The long-running saga between Redmond and the disgruntled cybersecurity expert got a couple of new chapters this week, thanks to the release of the RoguePlanet and GreatXML exploits. RoguePlanet is probably the nastiest one, as it takes advantage of yet another vulnerability in Windows Defender to gain SYSTEM user access privileges, letting an attacker execute commands at a privilege level even higher than the standard Administrator. The practical mechanism is simple: just fool a user into running a script, and said script will get full access to the machine, granting the ability to syphon all data, keep exfiltration malware installed, or any other number of malicious activities.…