A newly discovered botnet is compromising poorly-protected Linux servers by brute-forcing weak SSH password login authentication. Researchers at Canada-based Flare Systems, who discovered the botnet, got into its staging server and believe at least 7,000 servers had been compromised by the end of January, half of them in the US. The botnet’s weapons include exploits for unpatched Linux vulnerabilities going back as far as 2009. The researchers describe the botnet, dubbed SSHStalker, as “a sophisticated operation that blends 2009-era Internet Relay Chat (IRC) botnet tactics with modern mass-compromise automation.” It has a “stitched together botnet kit” that executes fileless malware, rootkit...