The Malurian system, also known as Maluria, was a planetary system in the Beta Quadrant. This system included four inhabited planets. It contained the Malurians, a warp-capable humanoid species. In the last census before its destruction, four billion people were counted in the system. (ENT: "Civilization"; TOS: "The Changeling")
In 2267, Dr. Manway sent a routine report. A week later, a distress call was sent from this system by the Malurians. The closest starship to this system, the USS Enterprise, responded to the call. It was determined, by the Enterprise, that the Malurian civilization as well as Dr. Manway's team had been destroyed by the probe Nomad, leaving the system lifeless. (TOS: "The Changeling")
In 2399, the location of Maluria was labeled in a Federation star chart that was in Fleet Admiral Kirsten Clancy's office at Starfleet Headquarters. This system was in or near to Federation space. (PIC: "Maps and Legends")
According to Star Trek: Star Charts (pp. 60, 66) and Stellar Cartography: The Starfleet Reference Library ("Federation Historical Highlights, 2161-2385"), the primary of the Malurian system, named Maluria (Epsilon Fornacis), was a G-class star.