CVE-2021-22681
Published on March 3, 2021
Rockwell Automation Studio 5000 Logix Designer Versions 21 and later, and RSLogix 5000 Versions 16 through 20 use a key to verify Logix controllers are communicating with Rockwell Automation CompactLogix 1768, 1769, 5370, 5380, 5480: ControlLogix 5550, 5560, 5570, 5580; DriveLogix 5560, 5730, 1794-L34; Compact GuardLogix 5370, 5380; GuardLogix 5570, 5580; SoftLogix 5800. Rockwell Automation Studio 5000 Logix Designer Versions 21 and later and RSLogix 5000: Versions 16 through 20 are vulnerable because an unauthenticated attacker could bypass this verification mechanism and authenticate with Rockwell Automation CompactLogix 1768, 1769, 5370, 5380, 5480: ControlLogix 5550, 5560, 5570, 5580; DriveLogix 5560, 5730, 1794-L34; Compact GuardLogix 5370, 5380; GuardLogix 5570, 5580; SoftLogix 5800.
Known Exploited Vulnerability
This Rockwell Multiple Products Insufficient Protected Credentials Vulnerability is part of CISA's list of Known Exploited Vulnerabilities. Multiple Rockwell products contain an insufficient protected credentials vulnerability. Studio 5000 Logix Designer software may allow a key to be discovered. This key is used to verify Logix controllers are communicating with Rockwell Automation design software. If successfully exploited, this vulnerability could allow an unauthorized application to connect with Logix controllers. To leverage this vulnerability, an unauthorized user would require network access to the controller.
The following remediation steps are recommended / required by March 26, 2026: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Vulnerability Analysis
CVE-2021-22681 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. This vulnerability is known to be actively exploited by threat actors in an automatable fashion. The potential impact of an exploit of this vulnerability is considered to be critical as this vulnerability has a high impact to the confidentiality, integrity and availability of this component.
Weakness Type
Insufficiently Protected Credentials
The product transmits or stores authentication credentials, but it uses an insecure method that is susceptible to unauthorized interception and/or retrieval.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.