SHARPEXT is a malicious browser extension deployed by SharpTongue (N.Korea) following successful compromise of a target system. SHARPEXT is after your emails and private data. 

The first versions of SHARPEXT only targeted Chrome but later versions hit Chrome, Edge, Whale...

This extension gets installed in your browser without your knowledge. The first step is to install malware on your PC. Once the malware infects your device, the malicious SHARPEXT extension is installed in your browser. 

Read more at Volexity...