CVE-2021-33541 - CVE House
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Status published High CVE-2021-33541

Phoenix Contact: ILC1x Industrial controllers affected by Denial-of-Service vulnerability

Vulnerability Description

Phoenix Contact Classic Line Controllers ILC1x0 and ILC1x1 in all versions/variants are affected by a Denial-of-Service vulnerability. The communication protocols and device access do not feature authentication measures. Remote attackers can use specially crafted IP packets to cause a denial of service on the PLC's network communication module. A successful attack stops all network communication. To restore the network connectivity the device needs to be restarted. The automation task is not affected.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

The following person or organization is credited with identifying this vulnerability, as recorded in the NVD database:

  • This vulnerability was discovered by the Industrial Control Security Laboratory of Qi An Xin Technology Group Inc. from China and reported to CERT@VDE. PHOENIX CONTACT thanks CERT@VDE for the coordination and support with this publication.

Affected Vendor

Phoenix Contact

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Affected Software

ILC1x
Vulnerable Versions:
ILC1x0 all variants, ILC1x1 all variants

Timeline

Official Publish: June 25th, 2021
Last Modified: September 16th, 2024
Added to House: July 21st, 2026

CVSS Vectors

V3: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Weaknesses (CWE)