Talos recently discovered a vulnerability in Allen-Bradley Rockwell Automation MicroLogix 1400 Programmable Logic Controllers (PLCs) This vulnerability is due to the presence of an undocumented SNMP community string that could be leveraged by an attacker to gain full control of affected devices. The vulnerability grants the ability to manipulate configuration settings, replace the firmware running on the device with attacker-controlled code, or otherwise disrupt device operations. Depending on the role of the affected PLC within an industrial control process, this could result in significant damages.”]
Source: https://blog.talosintelligence.com/2016/08/rockwell-snmp-vuln.html