Basarnud is a small cave in the Boethiah's Spine containing bandits. The cave really is in the middle of nowhere, being roughly equidistant from Tel Muthada, Alt Bosara, and Adurin-Ouaka. The easiest way to find it is to reach the Dulun-Sarethi Egg Mine then head north into the hills, take the first valley on your left then keep an eye on the southern hills for the entrance.
The bandits inside seem to have an eclectic taste in goods. There are five bottles of skooma to be found, along with a barrel of moon sugar, but the rest of their good are the usual mix of weapons, armor and other random items.