Siemens SIMATIC S7-200 SMART Devices Vulnerability Alert

Siemens SIMATIC S7-200 SMART Devices Vulnerability Alert

Executive Summary

A vulnerability has been identified in Siemens SIMATIC S7-200 SMART Devices, classified as Uncontrolled Resource Consumption. The vulnerability has a CVSS v4 score of 8.7, indicating a high-risk exploit with low attack complexity, and can be remotely exploited.

Risk Evaluation

Successful exploitation of this vulnerability could allow an attacker to cause a denial-of-service (DoS) condition, effectively disrupting the affected systems.

Affected Products

All versions of the following Siemens SIMATIC S7-200 SMART Devices are affected:

• SIMATIC S7-200 SMART CPU CR40 (6ES7288-1CR40-0AA0)
• SIMATIC S7-200 SMART CPU CR60 (6ES7288-1CR60-0AA0)
• SIMATIC S7-200 SMART CPU SR20 (6ES7288-1SR20-0AA0, 6ES7288-1SR20-0AA1)
• SIMATIC S7-200 SMART CPU SR30 (6ES7288-1SR30-0AA0, 6ES7288-1SR30-0AA1)
• SIMATIC S7-200 SMART CPU SR40 (6ES7288-1SR40-0AA0, 6ES7288-1SR40-0AA1)
• SIMATIC S7-200 SMART CPU SR60 (6ES7288-1SR60-0AA0, 6ES7288-1SR60-0AA1)
• SIMATIC S7-200 SMART CPU ST20 (6ES7288-1ST20-0AA0, 6ES7288-1ST20-0AA1)
• SIMATIC S7-200 SMART CPU ST30 (6ES7288-1ST30-0AA0, 6ES7288-1ST30-0AA1)
• SIMATIC S7-200 SMART CPU ST40 (6ES7288-1ST40-0AA0, 6ES7288-1ST40-0AA1)
• SIMATIC S7-200 SMART CPU ST60 (6ES7288-1ST60-0AA0, 6ES7288-1ST60-0AA1)

Vulnerability Overview: CWE-400 (Uncontrolled Resource Consumption)

The affected devices do not handle TCP packets with an incorrect structure properly. This flaw allows an unauthenticated remote attacker to trigger a denial-of-service condition. To restore normal functionality, the network cable needs to be unplugged and reconnected.

CVE-2024-43647 has been assigned to this vulnerability, with a CVSS v3.1 score of 7.5 and a CVSS v4 score of 8.7.

Background Information

• Critical Infrastructure Sectors: Critical Manufacturing
• Deployment Areas: Worldwide
• Company Headquarters: Germany

Mitigations

Siemens has outlined several workarounds and best practices to reduce the risk associated with this vulnerability:

1. Limit Network Access: Ensure that only trusted users and systems can access network devices.
2. General Security Measures:
   • Protect network access to devices using appropriate security mechanisms.
   • Operate devices in protected IT environments and configure them according to Siemens' guidelines for industrial security.
   • Follow the recommendations in product manuals to mitigate risks.

For further inquiries regarding security vulnerabilities, users should contact Siemens ProductCERT. More information can be found in the Siemens security advisory SSA-969738.

Additional Mitigation Recommendations

CISA has provided the following defensive strategies to minimize the risk of exploitation:

• Minimize Network Exposure: Ensure that control system devices and systems are not accessible from the internet.
• Use Firewalls and Segmentation: Place control system networks and remote devices behind firewalls, isolating them from business networks.
• Use VPNs for Remote Access: If remote access is required, use Virtual Private Networks (VPNs) but ensure they are up to date. Keep in mind that VPN security also depends on the security of connected devices.

Defensive Measures from CISA

CISA encourages organizations to:

• Perform impact analysis and risk assessments before deploying defensive measures.
• Implement best cybersecurity practices for industrial control systems (ICS), including defense-in-depth strategies as outlined in available CISA resources.

For further guidance, visit the ICS section of the CISA website, where additional best practices and technical resources are available, including the technical paper ICS-TIP-12-146-01B—Targeted Cyber Intrusion Detection and Mitigation Strategies.

Reporting and Awareness

Organizations observing suspected malicious activity should follow their established procedures and report findings to CISA for tracking and correlation.

To defend against social engineering attacks, CISA advises:

• Avoid clicking on unsolicited web links or opening attachments in emails.
• Refer to resources on Recognizing and Avoiding Email Scams and Avoiding Social Engineering and Phishing Attacks for more information.

At the time of this report, no public exploitation specifically targeting this vulnerability has been reported.