Ivanti Pulse Secure was using decade-old Linux and outdated libraries — no wonder it was such a popular target for hackers

A person's fingers type at a keyboard, with a digital security screen with a lock on it overlaid.

Knowing which operating system, as well as libraries, Ivanti Pulse Secure used, it is no wonder hackers keep finding new zero-day vulnerabilities to exploit.

That's the conclusion of security analysts from Eclypsium, who analyzed firmware version 9.1.18.2-24467.1 and concluded that the operating system used was CentOS 6.4.