SSH private keys are being targeted by hackers who have stepped up their scanning of thousands of servers hosting WordPress websites in search of private keys. Since Monday, security researchers said they have observed a single entity scanning as many as 25,000 systems a day seeking vulnerable SSH keys to be used to compromise websites.
“What triggered our concern was a customer who notified us that they have been monitoring their live traffic and seeing scans for SSH keys,” said WordFence CEO Mark Maunder, in an interview with Threatpost. “When we examined our own honeypots we found that this was not an isolated case and that 25,000 scans were taking place in waves each day.”
Those scans began on Monday and are ongoing, Maunder said and reported in a blog post. Adversaries are using terms such as “root,” “ssh,” or “id_rsa” in hopes of finding web directories containing private SSH keys, most likely mistakenly stored on public directories.
SSH (Secure Shell) is a cryptographic network protocol most often used for secure remote logins to remote computer systems. Successful theft of a private key would give a threat actor access to any server or system where that private key is used for authentication. That risk, security experts note, is not just limited to WordPress but also Linux and Unix systems and embedded devices that also rely heavily on SSH for secure logins and connections.