Modicon M340 CPU (part numbers BMXP34*): Authentication Bypass by Spoofing
CVE-2024-8935 is a high-severity authentication bypass by spoofing vulnerability in Modicon M340 CPU (part numbers BMXP34*) from Schneider Electric, 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, but only if a user takes part, for example by opening a link or file. Affected Modicon M340 CPU (part numbers BMXP34*) versions: All versions since SV3.60. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.52% 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 Modicon M340 CPU (part numbers BMXP34*) you run against the affected versions below, and install the vendor's latest release.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
- Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Schneider Electric | Modicon M340 CPU (part numbers BMXP34*) | All versions since SV3.60 | Not stated |
| Schneider Electric | Modicon MC80 (part numbers BMKC80) | All versions | Not stated |
| Schneider Electric | Modicon Momentum Unity M1E Processor (171CBU*) | All Versions | Not stated |
| Schneider Electric | modicon_m340_bmxp341000 | SV3.60 and later | Not stated |
| Schneider Electric | modicon_mc80_bmkc8020301 | all versions | Not stated |
| Schneider Electric | modicon_momentum_unity_m1e_processor | all versions | 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
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- RequiredA user must take an action such as opening a file or link.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by CNA (se.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 7.7 | High | CNA (se.com) |
| CVSS 3.1 | 7.5 | High | CNA (se.com) |
Official description
CWE-290: Authentication Bypass by Spoofing vulnerability exists that could cause a denial of service and loss of confidentiality and integrity of controllers when conducting a Man-In-The-Middle attack between the controller and the engineering workstation while a valid user is establishing a communication session. This vulnerability is inherent to Diffie Hellman algorithm which does not protect against Man-In-The-Middle attacks.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Authentication Bypass by Spoofing
This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.
More Authentication Bypass by Spoofing vulnerabilities (CWE-290)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in Modicon M340 CPU (part numbers BMXP34*)
- 8.1 High severity
- 7.5 High severity
- 8.1 High severity
- 7.5 High severity
- 9.8 Critical severity
- 9.8 Critical severity
Recent Authentication Bypass by Spoofing vulnerabilities
- 9.1 Critical severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 9.8 Critical severity
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