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Deserialization of Untrusted DataWeakness · CWE-502

CVE-2023-32735

MEDIUM · 6.5 CVSS v3.1 Published 2024-07-09
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
65/100
Remediation priority · Elevated

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A vulnerability has been identified in SIMATIC STEP 7 Safety V16 (All versions < V16 Update 7), SIMATIC STEP 7 Safety V17 (All versions < V17 Update 7), SIMATIC STEP 7 Safety V18 (All versions < V18 Update 2), SIMATIC STEP 7 V16 (All versions < V16 Update 7), SIMATIC STEP 7 V17 (All versions < V17 Update 7), SIMATIC STEP 7 V18 (All versions < V18 Update 2), SIMATIC WinCC Unified V16 (All versions < V16 Update 7), SIMATIC WinCC Unified V17 (All versions < V17 Update 7), SIMATIC WinCC Unified V18 (All versions < V18 Update 2), SIMATIC WinCC V16 (All versions < V16.7), SIMATIC WinCC V17 (All versions < V17.7), SIMATIC WinCC V18 (All versions < V18 Update 2), SIMOCODE ES V16 (All versions < V16 Update 7), SIMOCODE ES V17 (All versions < V17 Update 7), SIMOCODE ES V18 (All versions < V18 Update 2), SIMOTION SCOUT TIA V5.4 SP1 (All versions), SIMOTION SCOUT TIA V5.4 SP3 (All versions), SIMOTION SCOUT TIA V5.5 SP1 (All versions), SINAMICS Startdrive V16 (All versions), SINAMICS Startdrive V17 (All versions), SINAMICS Startdrive V18 (All versions), SIRIUS Safety ES V17 (All versions < V17 Update 7), SIRIUS Safety ES V18 (All versions < V18 Update 2), SIRIUS Soft Starter ES V17 (All versions < V17 Update 7), SIRIUS Soft Starter ES V18 (All versions < V18 Update 2), Soft Starter ES V16 (All versions < V16 Update 7), TIA Portal Cloud V3.0 (All versions < V18 Update 2). Affected applications do not properly restrict the .NET BinaryFormatter when deserializing hardware configuration profiles. This could allow an attacker to cause a type confusion and execute arbitrary code within the affected application. This is the same issue that exists for .NET BinaryFormatter https://docs.microsoft.com/en-us/visualstudio/code-quality/ca2300.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The vulnerability exists in multiple Siemens TIA Portal and engineering applications (STEP 7, WinCC, SIMOTION, SINAMICS, etc.) that use .NET BinaryFormatter to deserialize hardware configuration profiles without proper restrictions. An attacker could craft a malicious configuration file that, when deserialized by the application, causes type confusion leading to arbitrary code execution within the affected application's context.

MitigationApply vendor-supplied updates: STEP 7/STEP 7 Safety V16 to Update 7, V17 to Update 7, V18 to Update 2; WinCC/WinCC Unified V16 to Update 7/V16.7, V17 to Update 7/V17.7, V18 to Update 2; and corresponding updates for all other affected products. Avoid opening untrusted hardware configuration files.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
High
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed Siemens TIA Portal or engineering applications
    Open Windows Control Panel > Programs and Features, or use 'Get-ItemProperty' PowerShell command to list installed software containing names like 'STEP 7', 'WinCC', 'SIMOTION', 'SINAMICS', or 'TIA Portal'
    Affected if Any of these Siemens engineering applications are installed on the system
  2. Determine the exact version of the installed Siemens software
    Within the installed program, navigate to Help > About, or check the program files directory for version information. For TIA Portal, the version is typically displayed in the portal's title bar or Help > About dialog
    Affected if The installed version falls within V16 (prior to Update 7), V17 (prior to Update 7), or V18 (prior to Update 2)
  3. Check the installed update level for the Siemens product
    In Windows Control Panel > Programs and Features, look for update entries under the Siemens product name, or check the program's Help > About section which usually displays both version and update package information
    Affected if The product shows an update level earlier than the patched versions (Update 7 for V16/V17, Update 2 for V18)
  4. Inspect the environment for presence of hardware configuration files
    Search the file system for common Siemens configuration file extensions such as .sdf, .bak, .ap16, .ap17, .ap18, or other hardware configuration files typically stored in project directories
    Affected if Hardware configuration files from untrusted or unknown sources are present and could be opened by the vulnerable application

The environment is affected if any Siemens TIA Portal, STEP 7, WinCC, SIMOTION, or SINAMICS engineering software is installed with a version prior to Update 7 for V16/V17 or prior to Update 2 for V18.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply vendor-supplied updates: STEP 7/STEP 7 Safety V16 to Update 7, V17 to Update 7, V18 to Update 2; WinCC/WinCC Unified V16 to Update 7/V16.7, V17 to Update 7/V17.7, V18 to Update 2; and corresponding updates for all other affected products. Avoid opening untrusted hardware configuration files.

Recommended fix High confidence

V16 Update 7, V17 Update 7, V18 Update 2 (or V16.7/V17.7 for WinCC V16/V17) depending on product line

  1. 1. Identify the specific Siemens software product(s) installed from the affected list (SIMATIC STEP 7, SIMATIC WinCC, SIMOCODE ES, SIMOTION SCOUT TIA, SINAMICS Startdrive, SIRIUS Safety ES, SIRIUS Soft Starter ES, Soft Starter ES, or TIA Portal Cloud).
  2. 2. Determine the current version of the installed product(s) using the application's About or Help menu.
  3. 3. For SIMATIC STEP 7 Safety, STEP 7, WinCC, WinCC Unified, SIMOCODE ES: upgrade to V16 Update 7, V17 Update 7, or V18 Update 2 respectively.
  4. 4. For SIMATIC WinCC V16: upgrade to V16.7. For V17: upgrade to V17.7. For V18: upgrade to V18 Update 2.
  5. 5. For SIMOTION SCOUT TIA: Note that V5.4 SP1, V5.4 SP3, and V5.5 SP1 are listed as 'All versions' affected with no fixed version specified in the advisory - contact Siemens for patch availability.
  6. 6. For SINAMICS Startdrive V16/V17/V18: Contact Siemens for patch availability as no fixed version is specified.
  7. 7. For SIRIUS Safety ES and SIRIUS Soft Starter ES: upgrade to V17 Update 7 or V18 Update 2.
  8. 8. For Soft Starter ES V16: upgrade to V16 Update 7.
Caveat Upgrades may require project migration or compatibility verification with existing hardware configurations; test in non-production environment first

Generated from the published advisory — verify against the referenced sources before acting.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-32735 in production — separate from our analysis above.

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