SIMATIC MV540 H: Missing Authentication for Critical Functionality
CVE-2022-33138 is a high-severity missing authentication for critical functionality vulnerability in SIMATIC MV540 H 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 MV540 H versions: All versions < V3.3. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 1.38% chance of exploitation within 30 days, higher than 73% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Simatic Mv540 H Firmware to 3.3 or a later version.
- Update Simatic Mv540 S Firmware to 3.3 or a later version.
- Update Simatic Mv550 H Firmware to 3.3 or a later version.
- 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 MV540 H | All versions < V3.3 | Not stated |
| Siemens | SIMATIC MV540 S | All versions < V3.3 | Not stated |
| Siemens | SIMATIC MV550 H | All versions < V3.3 | Not stated |
| Siemens | SIMATIC MV550 S | All versions < V3.3 | Not stated |
| Siemens | SIMATIC MV560 U | All versions < V3.3 | Not stated |
| Siemens | SIMATIC MV560 X | All versions < V3.3 | Not stated |
| Siemens | Simatic Mv540 H Firmware | before 3.3 | 3.3 |
| Siemens | Simatic Mv540 S Firmware | before 3.3 | 3.3 |
| Siemens | Simatic Mv550 H Firmware | before 3.3 | 3.3 |
| Siemens | Simatic Mv550 S Firmware | before 3.3 | 3.3 |
| Siemens | Simatic Mv560 U Firmware | before 3.3 | 3.3 |
| Siemens | Simatic Mv560 X Firmware | before 3.3 | 3.3 |
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
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.5 | High | NVD |
| CVSS 2.0 | 5.0 | Medium | NVD |
Official description
A vulnerability has been identified in SIMATIC MV540 H (All versions < V3.3), SIMATIC MV540 S (All versions < V3.3), SIMATIC MV550 H (All versions < V3.3), SIMATIC MV550 S (All versions < V3.3), SIMATIC MV560 U (All versions < V3.3), SIMATIC MV560 X (All versions < V3.3). Affected devices do not perform authentication for several web API endpoints. This could allow an unauthenticated remote attacker to read and download data from the device.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Missing Authentication for Critical Functionality
The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.
How developers prevent this class of flaw
- For any security checks that are performed on the client side, ensure that these checks are duplicated on the server side, in order to avoid CWE-602. Attackers can bypass the client-side checks by modifying values after the checks have been performed, or by changing the client to remove the client-side checks entirely. Then, these modified values would be submitted to the server.
- Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using libraries with authentication capabilities such as OpenSSL or the ESAPI Authenticator.
- When storing data in the cloud (e.g., S3 buckets, Azure blobs, Google Cloud Storage, etc.), use the provider's controls to require strong authentication for users who should be allowed to access the data.
More Missing Authentication for Critical Functionality vulnerabilities (CWE-306)
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in SIMATIC MV540 H
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
- 8.0 High severity
Recent Missing Authentication for Critical Functionality vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 9.8 Critical severity
- 7.5 High severity
- 9.8 Critical severity
- 9.8 Critical severity
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