SIMATIC CP 343-1: Improper Verification of Source of a Communication Channel
CVE-2023-51440 is a high-severity improper verification of source of a communication channel vulnerability in SIMATIC CP 343-1 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 CP 343-1 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 0.6% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Check which version of SIMATIC CP 343-1 you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on cert-portal.siemens.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Siemens | SIMATIC CP 343-1 | All versions | Not stated |
| Siemens | SIMATIC CP 343-1 Lean | All versions | Not stated |
| Siemens | SIPLUS NET CP 343-1 | All versions | Not stated |
| Siemens | SIPLUS NET CP 343-1 Lean | All versions | Not stated |
| Siemens | Simatic Cp 343-1 Firmware | Not specified in the record | Not stated |
| Siemens | Simatic Cp 343-1 Lean Firmware | Not specified in the record | Not stated |
| Siemens | Siplus Net Cp 343-1 Firmware | Not specified in the record | Not stated |
| Siemens | Siplus Net Cp 343-1 Lean Firmware | Not specified in the record | Not 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 NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | CNA (siemens.com) |
| CVSS 3.1 | 7.5 | High | NVD |
Official description
A vulnerability has been identified in SIMATIC CP 343-1 (6GK7343-1EX30-0XE0) (All versions), SIMATIC CP 343-1 Lean (6GK7343-1CX10-0XE0) (All versions), SIPLUS NET CP 343-1 (6AG1343-1EX30-7XE0) (All versions), SIPLUS NET CP 343-1 Lean (6AG1343-1CX10-2XE0) (All versions). Affected products incorrectly validate TCP sequence numbers. This could allow an unauthenticated remote attacker to create a denial of service condition by injecting spoofed TCP RST packets.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Verification of Source of a Communication Channel
The product establishes a communication channel to handle an incoming request that has been initiated by an actor, but it does not properly verify that the request is coming from the expected origin.
How developers prevent this class of flaw
- Use a mechanism that can validate the identity of the source, such as a certificate, and validate the integrity of data to ensure that it cannot be modified in transit using an Adversary-in-the-Middle (AITM) attack. When designing functionality of actions in the URL scheme, consider whether the action should be accessible to all mobile applications, or if an allowlist of applications to interface with is appropriate.
More Improper Verification of Source of a Communication Channel vulnerabilities (CWE-940)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Recent Improper Verification of Source of a Communication Channel vulnerabilities
- 8.8 High severity
- 8.8 High severity
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