Schneider Electric Modicon PLCs Predictable Value Range From Previous Values (CVE-2017-6030)

medium Tenable OT Security Plugin ID 500867

Synopsis

The remote OT asset is affected by a vulnerability.

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.

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Solution

The following text was originally created by the Cybersecurity and Infrastructure Security Agency (CISA). The original can be found at CISA.gov.

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/

Plugin Details

Severity: Medium

ID: 500867

Version: 1.7

Type: remote

Family: Tenable.ot

Published: 3/1/2023

Updated: 3/4/2024

Supported Sensors: Tenable OT Security

Risk Information

VPR

Risk Factor: Low

Score: 2.5

CVSS v2

Risk Factor: Medium

Base Score: 6.4

Temporal Score: 4.7

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

CVSS Score Source: CVE-2017-6030

CVSS v3

Risk Factor: Medium

Base Score: 6.5

Temporal Score: 5.7

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

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

Vulnerability Information

CPE: cpe:/o:schneider-electric:modicon_m221_series_firmware, cpe:/o:schneider-electric:modicon_m241_series_firmware, cpe:/o:schneider-electric:modicon_m251_series_firmware

Required KB Items: Tenable.ot/Schneider

Exploit Ease: No known exploits are available

Patch Publication Date: 6/30/2017

Vulnerability Publication Date: 6/30/2017

Reference Information

CVE: CVE-2017-6030

CWE: 331

Detections

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