Description
A predictable value range from previous values issue was discovered in Schneider Electric Modicon PLCs Modicon M221, firmware versions prior to Version 1.5.0.0, Modicon M241, firmware versions prior to Version 4.0.5.11, and Modicon M251, firmware versions prior to Version 4.0.5.11. The affected products generate insufficiently random TCP initial sequence numbers that may allow an attacker to predict the numbers from previous values. This may allow an attacker to spoof or disrupt TCP connections.
Published: 2017-06-30
Score: 6.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

No analysis available yet.

Remediation

Vendor Solution

Schneider Electric has released new firmware versions to address the predictable value range from previous values vulnerability and the use of insufficiently random values vulnerability, which are available through Schneider Electric’s software update tool, SoMachine, Version 4.2, and SoMachineBasic, Version 1.5. Schneider Electric has not released a product to address the insufficiently protected credentials vulnerability; however, Schneider Electric has provided compensating controls to reduce the risk of exploitation. SoMachineBasic, Version 1.5, is available at the following location: http://www.schneider-electric.fr/fr/download/document/SOMBASAP15SOFT/  Schneider Electric has provided the following compensating controls to reduce the risk of exploitation of the insufficiently protected credentials vulnerability: * Verify that the hardware and software infrastructure that the PLCs are integrated into (along with all organizational measures and rules covering access to the infrastructure) consider the results of the hazard and risk analysis, and are implemented according to best practices and standards such as ISA/IEC 62443. * Limit traffic on the local network with managed switches * Where possible, avoid using Wi-Fi networks, but when Wi-Fi is essential, use only secure communications (such as WPA2 encryption) * Do not grant [network] access to unknown computers * When remote access is essential, use secure methods such as Virtual Private Networks (VPNs), and ensure the remote access solution(s), as well as the remote computer(s) are kept up-to-date with the latest security patches. Schneider Electric has released Security Notifications SEVD-2017-075-01, SEVD-2017-075-02, and SEVD-2017-075-03, which provide additional information about the identified vulnerabilities, mitigations, and compensating controls: http://www.schneider-electric.com/en/download/document/SEVD-2017-075-01/ http://www.schneider-electric.com/en/download/document/SEVD-2017-075-02/ http://www.schneider-electric.com/en/download/document/SEVD-2017-075-03/

Tracking

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Advisories
Source ID Title
EUVD EUVD EUVD-2017-15098 A Predictable Value Range from Previous Values issue was discovered in Schneider Electric Modicon PLCs Modicon M221, firmware versions prior to Version 1.5.0.0, Modicon M241, firmware versions prior to Version 4.0.5.11, and Modicon M251, firmware versions prior to Version 4.0.5.11. The affected products generate insufficiently random TCP initial sequence numbers that may allow an attacker to predict the numbers from previous values. This may allow an attacker to spoof or disrupt TCP connections.
History

Thu, 04 Jun 2026 22:15:00 +0000

Type Values Removed Values Added
Description A Predictable Value Range from Previous Values issue was discovered in Schneider Electric Modicon PLCs Modicon M221, firmware versions prior to Version 1.5.0.0, Modicon M241, firmware versions prior to Version 4.0.5.11, and Modicon M251, firmware versions prior to Version 4.0.5.11. The affected products generate insufficiently random TCP initial sequence numbers that may allow an attacker to predict the numbers from previous values. This may allow an attacker to spoof or disrupt TCP connections. A predictable value range from previous values issue was discovered in Schneider Electric Modicon PLCs Modicon M221, firmware versions prior to Version 1.5.0.0, Modicon M241, firmware versions prior to Version 4.0.5.11, and Modicon M251, firmware versions prior to Version 4.0.5.11. The affected products generate insufficiently random TCP initial sequence numbers that may allow an attacker to predict the numbers from previous values. This may allow an attacker to spoof or disrupt TCP connections.
Title Schneider Electric Modicon PLCs Predictable Value Range from Previous Values
References

Fri, 29 May 2026 14:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Subscriptions

Schneider-electric Modicon M221 Modicon M221 Firmware Modicon M241 Modicon M241 Firmware Modicon M251 Modicon M251 Firmware
cve-icon MITRE

Status: PUBLISHED

Assigner: icscert

Published:

Updated: 2026-06-04T21:40:02.867Z

Reserved: 2017-02-16T00:00:00.000Z

Link: CVE-2017-6030

cve-icon Vulnrichment

Updated: 2024-08-05T15:18:49.582Z

cve-icon NVD

Status : Modified

Published: 2017-06-30T03:29:00.390

Modified: 2026-06-04T22:16:50.067

Link: CVE-2017-6030

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses