CyberSecBulletin
CVE-2024-43647NVD status: Deferred

SIMATIC S7-200 SMART CPU CR40: Uncontrolled Resource Consumption

Published Updated By the CyberSecBulletin desk

CVE-2024-43647 is a high-severity uncontrolled resource consumption vulnerability in SIMATIC S7-200 SMART CPU CR40 from Siemens, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected SIMATIC S7-200 SMART CPU CR40 versions: all versions. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.56% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of SIMATIC S7-200 SMART CPU CR40 you run against the affected versions below, and install the vendor's latest release.
  2. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.

Affected products and versions

VendorProductAffected versionsFixed in
SiemensSIMATIC S7-200 SMART CPU CR40all versionsNot stated
SiemensSIMATIC S7-200 SMART CPU CR60all versionsNot stated
SiemensSIMATIC S7-200 SMART CPU SR20all versionsNot stated
SiemensSIMATIC S7-200 SMART CPU SR30all versionsNot stated
SiemensSIMATIC S7-200 SMART CPU SR40all versionsNot stated
SiemensSIMATIC S7-200 SMART CPU SR60all versionsNot stated
SiemensSIMATIC S7-200 SMART CPU ST20all versionsNot stated
SiemensSIMATIC S7-200 SMART CPU ST30all versionsNot stated
SiemensSIMATIC S7-200 SMART CPU ST40all versionsNot stated
SiemensSIMATIC S7-200 SMART CPU ST60all versionsNot stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
NoneNo action by a victim is required.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
NoneNo data is disclosed.
Integrity
NoneNothing can be modified.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CNA (siemens.com).

Scoring systemScoreSeverityScored by
CVSS 4.08.7HighCNA (siemens.com)
CVSS 3.17.5HighCNA (siemens.com)

Official description

A vulnerability has been identified in SIMATIC S7-200 SMART CPU CR40 (6ES7288-1CR40-0AA0) (All versions), SIMATIC S7-200 SMART CPU CR60 (6ES7288-1CR60-0AA0) (All versions), SIMATIC S7-200 SMART CPU SR20 (6ES7288-1SR20-0AA0) (All versions), SIMATIC S7-200 SMART CPU SR20 (6ES7288-1SR20-0AA1) (All versions), SIMATIC S7-200 SMART CPU SR30 (6ES7288-1SR30-0AA0) (All versions), SIMATIC S7-200 SMART CPU SR30 (6ES7288-1SR30-0AA1) (All versions), SIMATIC S7-200 SMART CPU SR40 (6ES7288-1SR40-0AA0) (All versions), SIMATIC S7-200 SMART CPU SR40 (6ES7288-1SR40-0AA1) (All versions), SIMATIC S7-200 SMART CPU SR60 (6ES7288-1SR60-0AA0) (All versions), SIMATIC S7-200 SMART CPU SR60 (6ES7288-1SR60-0AA1) (All versions), SIMATIC S7-200 SMART CPU ST20 (6ES7288-1ST20-0AA0) (All versions), SIMATIC S7-200 SMART CPU ST20 (6ES7288-1ST20-0AA1) (All versions), SIMATIC S7-200 SMART CPU ST30 (6ES7288-1ST30-0AA0) (All versions), SIMATIC S7-200 SMART CPU ST30 (6ES7288-1ST30-0AA1) (All versions), SIMATIC S7-200 SMART CPU ST40 (6ES7288-1ST40-0AA0) (All versions), SIMATIC S7-200 SMART CPU ST40 (6ES7288-1ST40-0AA1) (All versions), SIMATIC S7-200 SMART CPU ST60 (6ES7288-1ST60-0AA0) (All versions), SIMATIC S7-200 SMART CPU ST60 (6ES7288-1ST60-0AA1) (All versions). Affected devices do not properly handle TCP packets with an incorrect structure. This could allow an unauthenticated remote attacker to cause a denial of service condition. To restore normal operations, the network cable of the device needs to be unplugged and re-plugged.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Uncontrolled Resource Consumption

The product does not properly control the allocation and maintenance of a limited resource.

How developers prevent this class of flaw

  • Ensure that protocols have specific limits of scale placed on them.
  • Ensure that all failures in resource allocation place the system into a safe posture.

More Uncontrolled Resource Consumption vulnerabilities (CWE-400)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Other vulnerabilities in SIMATIC S7-200 SMART CPU CR40

All SIMATIC S7-200 SMART CPU CR40 vulnerabilities

Recent Uncontrolled Resource Consumption vulnerabilities

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