Affected devices improperly handle large amounts of specially crafted UDP packets. This could allow an unauthenticated remote attacker to trigger a denial of service condition.

An attacker with network access to an affected product may cause a denial of service condition by breaking the real-time synchronization (IRT) of the affected installation.

Specially crafted PROFINET DCP packets sent on a local Ethernet segment (Layer 2) to an affected product could cause a denial of service condition of that product. Human interaction is required to recover the system. PROFIBUS interfaces are not affected.

Specially crafted PROFINET DCP broadcast packets could cause a denial of service condition of affected products on a local Ethernet segment (Layer 2). Human interaction is required to recover the systems. PROFIBUS interfaces are not affected.

Siemens SINAMICS S/G controllers with firmware before 4.6.11 do not require authentication for FTP and TELNET sessions, which allows remote attackers to bypass intended access restrictions via TCP traffic to port (1) 21 or (2) 23.