Security readout for executives and security teams
Plain-English summary
This flaw can let an unauthenticated remote attacker crash affected Siemens SIMATIC MV540, MV550, and MV560 devices by sending specially crafted IP packets. The business impact is operational downtime: affected devices stop functioning and must be restarted manually.
Executive priority
Prioritize this for operational technology environments where these devices support production workflows. It is not a data theft issue, but a remote unauthenticated outage condition can still interrupt operations and require manual recovery.
Technical view
CVE-2023-35920 is a CWE-400 resource management issue affecting listed SIMATIC MV540/MV550/MV560 variants before V3.3.4. The attack is network-accessible, low-complexity, requires no privileges or user interaction, and impacts availability only. CVSS v3.1 is 7.5 high.
Likely exposure
Exposure is limited to environments running the listed Siemens SIMATIC MV540 H/S, MV550 H/S, MV560 U/X devices below V3.3.4, especially where device network interfaces are reachable by untrusted or poorly segmented networks.
Exploitation context
The provided sources do not show CISA KEV listing or confirmed active exploitation. Siemens and CVE data describe possible unauthenticated remote denial of service, with manual restart required after a successful availability impact.
Researcher notes
Evidence supports high availability risk with no confidentiality or integrity impact in the CVSS vector. The bundle does not provide exploit details, proof of active exploitation, or full Siemens mitigation text beyond the advisory reference and affected-version boundary.
Mitigation direction
- Identify affected SIMATIC MV540, MV550, and MV560 variants and firmware versions.
- Update devices below V3.3.4 according to Siemens SSA-561322 guidance.
- Review Siemens advisory for any device-specific remediation or operational constraints.
- Reduce network reachability to affected devices while remediation is planned.
- Prepare operational restart procedures for affected production environments.
Validation and detection
- Inventory all listed SIMATIC MV devices and record firmware versions.
- Confirm no listed device remains below V3.3.4 after remediation.
- Validate device network exposure from untrusted or non-operational segments.
- Monitor for unexpected device availability loss requiring manual restart.
- Document Siemens advisory review and remediation decisions.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
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CWE-400: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2023-35920 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C3.93.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C
Source materials
- CVE List V5 sourceCVE List V5
- https://cert-portal.siemens.com/productcert/pdf/ssa-561322.pdfCVE reference
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Uncontrolled Resource Consumption
Uncontrolled Resource Consumption represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.