[ZLib](https://attack.mitre.org/software/S0086) is a full-featured backdoor that was used as a second-stage implant during [Operation Dust Storm](https://attack.mitre.org/campaigns/C0016) since at least 2014. [ZLib](https://attack.mitre.org/software/S0086) is malware and should not be confused with the legitimate compression library from which its name is derived.(Citation: Cylance Dust Storm)