Rockwellautomation Flex Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

An exploitable denial of service vulnerability exists in the ENIP Request Path Data Segment functionality of Allen-Bradley Flex IO 1794-AENT/B. A specially crafted network request can cause a loss of communications with the device resulting in denial-of-service. An attacker can send a malicious packet to trigger this vulnerability If the ANSI Extended Symbol Segment Sub-Type is supplied, the device treats the byte following as the Data Size in words. When this value represents a size greater than what remains in the packet data, the device enters a fault state where communication with the device is lost and a physical power cycle is required.