A vulnerability has been identified in SIMATIC S7-300 CPU family (incl. related ET200 CPUs and SIPLUS variants) (All versions < V3.X.17), SIMATIC TDC CP51M1 (All versions < V1.1.8), SIMATIC TDC CPU555 (All versions < V1.1.1), SINUMERIK 840D sl (All versions < V4.8.6), SINUMERIK 840D sl (All versions < V4.94). Specially crafted packets sent to port 102/tcp (Profinet) could cause the affected device to go into defect mode. A restart is required in order to recover the system. Successful exploitation requires an attacker to have network access to port 102/tcp, with no authentication. No user interation is required. At the time of advisory publication no public exploitation of this security vulnerability was known.

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.