What is Log4j? An expert explains the latest internet vulnerability

Log4Shell, an internet vulnerability that affects millions of computers, involves an obscure but nearly ubiquitous piece of software, Log4j. The software is used to record all manner of activities that go on under the hood in a wide range of computer systems.

Jen Easterly, director of the U.S. Cybersecurity & Infrastructure Security Agency, called Log4Shell the most serious vulnerability she’s seen in her career. There have already been hundreds of thousands, perhaps millions, of attempts to exploit the vulnerability.

So what is this humble piece of internet infrastructure, how can hackers exploit it and what kind