ABB Central Licensing System (CVE-2020-8475)

high Tenable OT Security Plugin ID 500937


The remote OT asset is affected by a vulnerability.


For the Central Licensing Server component used in ABB products ABB Ability System 800xA and related system extensions versions 5.1, 6.0 and 6.1, Compact HMI versions 5.1 and 6.0, Control Builder Safe 1.0, 1.1 and 2.0, Symphony Plus -S+ Operations 3.0 to 3.2 Symphony Plus -S+ Engineering 1.1 to 2.2, Composer Harmony 5.1, 6.0 and 6.1, Melody Composer 5.3, 6.1/6.2 and SPE for Melody 1.0SPx (Composer 6.3), Harmony OPC Server (HAOPC) Standalone 6.0, 6.1 and 7.0, ABB Ability System 800xA/ Advant OCS Control Builder A 1.3 and 1.4, Advant OCS AC100 OPC Server 5.1, 6.0 and 6.1, Composer CTK 6.1 and 6.2, AdvaBuild 3.7 SP1 and SP2, OPCServer for MOD 300 (non-800xA) 1.4, OPC Data Link 2.1 and 2.2, Knowledge Manager 8.0, 9.0 and 9.1, Manufacturing Operations Management 1812 and 1909, ABB AbilityTM SCADAvantage versions 5.1 to 5.6.5, a weakness in validation of input exists that allows an attacker to block license handling by sending specially crafted messages to the CLS web service.

This plugin only works with Tenable.ot.
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The following text was originally created by the Cybersecurity and Infrastructure Security Agency (CISA). The original can be found at

ABB recommends the following mitigations:

- Upgrade ABB CLS to the following versions:
- 5.1 Rev A (
- 5.1 Rev E (
- 6.0 (
- (6.0.03000.192)
- 6.1 RU1 (6.1.00100.417)
- If ABB Central Licensing Server 5.1 ( or earlier has been used on the currently used hardware, please contact ABB for further assistance.
- Vulnerabilities pertaining to CVE-2020-8475 and CVE-2020-8476 will be corrected in future product versions. Updates will be added to this advisory once they become available.
- Methods for preventing unauthorized access to nodes on the CLS network include but are not limited to usage of IPSec and by separating the Client Server Network from other networks with firewalls.
- Ensure only authorized individuals have access to user accounts on the system nodes.
- Interactive login to service accounts should be blocked.

For more information, please see ABB's cybersecurity advisory.

See Also

Plugin Details

Severity: High

ID: 500937

Version: 1.3

Type: remote

Family: Tenable.ot

Published: 3/29/2023

Updated: 11/6/2023

Risk Information


Risk Factor: Low

Score: 3.6


Risk Factor: Low

Base Score: 2.1

Temporal Score: 1.6

Vector: CVSS2#AV:L/AC:L/Au:N/C:N/I:N/A:P

CVSS Score Source: CVE-2020-8475


Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/a:abb:800xa_system

Required KB Items: Tenable.ot/ABB

Exploit Ease: No known exploits are available

Patch Publication Date: 4/29/2020

Vulnerability Publication Date: 4/29/2020

Reference Information

CVE: CVE-2020-8475

CWE: 20