Dahua DVRs and IP cameras can be hacked in a matter of seconds. A security researcher found a simple way of hacking their devices. The attacker only has to access a URL in his browser to download the configuration file. After getting access to the device, they can do whatever they want, from uploading malware to reflashing the entire device with new firmware. Dahua devices have been a breeding ground for IoT botnets in the past two years, including recent DDoS attacks on KrebsOnSecurity and Dyn.
Source: https://www.bleepingcomputer.com/news/hardware/dahua-left-device-credentials-exposed-to-anyone-knowing-where-to-look/