PHASEJAM is a well-written and multifaceted bash shell script. It first installs a web shell that gives the remote hackers privileged control of devices. It then injects a function into the Connect Secure update mechanism that’s intended to simulate the upgrading process.

Hackers exploiting the critical Ivanti Connect Secure zero-day vulnerability disclosed yesterday installed on compromised VPN appliances new malware called 'Dryhook' and 'Phasejam' that is not currently associated with any threat group.

Ivanti is a major provider of infrastructure management and cybersecurity software with more than 40,000 customers. According to the company, those customers include several U.S. government agencies.