Phoenix Contact · Phoenix Contact Classic Line Controllers Ilc1X1 · CVE-2021-33541
**Name of the Vulnerable Software and Affected Versions**
Phoenix Contact Classic Line Controllers ILC1x0 and ILC1x1 (affected versions not specified)
**Description**
The issue is related to a Denial-of-Service condition where the communication protocols and device access lack authentication measures. Remote attackers can exploit this by sending specially crafted IP packets to cause a denial of service on the PLC's network communication module, effectively stopping all network communication. The automation task remains unaffected. To restore network connectivity, the device must be restarted.
**Recommendations**
At the moment, there is no information about a newer version that contains a fix for this vulnerability.