Security readout for executives and security teams
Plain-English summary
This affects Siemens SIMATIC STEP 7 Safety V18 before Update 2. A malicious or compromised local user with high privileges could abuse unsafe .NET BinaryFormatter deserialization to run code inside the engineering application. It matters most on safety engineering workstations, but the public record does not describe remote or active exploitation.
Executive priority
Treat this as a high-priority OT engineering workstation update, especially where STEP 7 Safety supports safety-related automation work. It is less urgent than a remotely exploitable internet-facing flaw, but compromise could affect trusted engineering tooling.
Technical view
The issue is CWE-502 unsafe deserialization. STEP 7 Safety V18 before Update 2 does not properly restrict .NET BinaryFormatter when deserializing user-controllable input, enabling type confusion and arbitrary code execution in the affected application context. CVSS 4.0 is 7.0 with local attack vector, low complexity, high privileges, and user interaction required.
Likely exposure
Organizations using SIMATIC STEP 7 Safety V18 earlier than V18 Update 2 are potentially exposed. Exposure appears workstation-focused, not internet-facing, based on the local attack vector. The sources do not specify the exact file, project, or input path involved.
Exploitation context
The supplied sources do not claim active exploitation, and CISA KEV is false. Exploitation is described as local, requiring high privileges and user interaction, with impact limited to the vulnerable application and host confidentiality, integrity, and availability.
Researcher notes
Evidence is limited to the CVE record and Siemens advisory reference. The record identifies BinaryFormatter deserialization and type confusion but does not name a file format, project artifact, public exploit, or detailed attack workflow. Avoid assuming network exposure.
Mitigation direction
- Update SIMATIC STEP 7 Safety V18 to Update 2 or later where applicable.
- Review Siemens SSA-313039 for product-specific remediation guidance.
- Limit affected engineering workstation access to trusted administrators.
- Avoid processing untrusted user-controllable input in affected versions.
- Apply compensating controls until all affected installs are updated.
Validation and detection
- Inventory all SIMATIC STEP 7 Safety V18 installations.
- Confirm each installation is V18 Update 2 or later.
- Check Siemens SSA-313039 for any environment-specific notes.
- Verify engineering workstations restrict access to authorized personnel.
- Document exceptions and compensating controls for unpatched systems.
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
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-502: Code execution behavior lookup
Code execution and unsafe deserialization weaknesses often justify reviewing execution behavior and process telemetry. 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 lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2023-32737 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 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
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:4.0/AV:L/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N——Primary CVE scoreVulnerability scoring details
Base CVSS 4.0 score
7HighVector: CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Source materials
- CVE List V5 sourceCVE List V5
- https://cert-portal.siemens.com/productcert/html/ssa-313039.htmlCVE 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.
Deserialization of Untrusted Data
Deserialization of Untrusted Data represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.