Full Report
SIMATIC S7-1200, S7-1500 CPUs and related products protect the built-in global private key in a way that cannot be considered sufficient any longer. The key is used for the legacy protection of confidential configuration data and the legacy PG/PC and HMI communication. This could allow attackers to discover the private key of a CPU product family by an offline attack against a single CPU of the family. Attackers could then use this knowledge to extract confidential configuration data from projects that are protected by that key or to perform attacks against legacy PG/PC and HMI communication. Siemens recommends to update both the affected products as well as the corresponding TIA Portal project to the latest versions. TIA Portal V17 and related CPU firmware versions introduced protection of confidential configuration data based on individual passwords per device and TLS-protected PG/PC and HMI communication. Additional details can be found in the related Siemens security bulletin SSB-898115 (https://cert-portal.siemens.com/productcert/html/ssb-898115.html).
Analysis Summary
# Vulnerability: Insufficient Protection of Global Private Keys in Siemens SIMATIC S7 CPUs
## CVE Details
- **CVE ID:** CVE-2022-38465
- **CVSS Score:** 9.3 (Critical) - *Note: Based on Siemens SSA-898115 analysis.*
- **CWE:** CWE-321: Use of Hard-coded Cryptographic Key; CWE-522: Insufficiently Protected Credentials.
## Affected Systems
- **Products:**
- SIMATIC S7-1200 CPU family
- SIMATIC S7-1500 CPU family (including ET 200SP, ET 200pro, Compact, and Software Controllers)
- SIMATIC S7-1500 SIPLUS variants
- SIMATIC Drive Controller
- SINUMERIK ONE
- **Versions:** All versions prior to those supporting TIA Portal V17 (specifically firmware versions prior to V2.9 for S7-1500 and V4.5 for S7-1200).
- **Configurations:** Systems utilizing "Legacy" protection modes for confidential configuration data and legacy PG/PC or HMI communication.
## Vulnerability Description
The affected Siemens product families rely on a built-in, global private key to secure confidential configuration data and facilitate communication between the CPU and Engineering Station (PG/PC) or HMI. The protection mechanism for this global key is no longer considered sufficient by modern standards. An attacker can perform an offline analysis of a single hardware PLC to extract this family-wide private key. Because the key is shared across product families, compromising one device compromises the entire line.
## Exploitation
- **Status:** Publicly documented/PoC available (Research presented at Black Hat USA 2022).
- **Complexity:** High (Requires sophisticated offline cryptographic analysis).
- **Attack Vector:** Local/Physical (to extract the key initially), then Network (to intercept/decrypt traffic).
## Impact
- **Confidentiality:** High (Extraction of sensitive project configuration and decryption of communication).
- **Integrity:** High (Potential for unauthorized configuration changes or man-in-the-middle attacks).
- **Availability:** None (Primary risk is data exposure and unauthorized access).
## Remediation
### Patches
Siemens recommends upgrading to TIA Portal V17 or higher and updating hardware firmware to enable modern security features:
- **SIMATIC S7-1200:** Update to Firmware V4.5 or later.
- **SIMATIC S7-1500:** Update to Firmware V2.9 or later.
- **Project Update:** The TIA Portal project must be updated to V17+ and the "Protection of confidential PLC configuration data" must be enabled using individual passwords per device.
### Workarounds
- **Use TLS Communication:** Configure PG/PC and HMI communication to use the "Secure PG/PC and HMI communication" mode introduced in V17, which utilizes TLS.
- **Physical Security:** Limit physical access to the PLC to prevent offline extraction of the key.
- **Network Segmentation:** Isolate industrial networks and use VPNs for remote access to prevent interception of legacy traffic.
## Detection
- **Indicators of Compromise:** Difficult to detect via standard logs as the attack involves offline key discovery and passive decryption.
- **Detection Methods:** Audit PLC configurations to ensure "Legacy" communication modes are disabled. Monitor for unauthorized PG/PC connections or unusual configuration upload/download requests.
## References
- **Siemens Security Advisory (SSB-898115):** hxxps[://]cert-portal[.]siemens[.]com/productcert/html/ssb-898115[.]html
- **Siemens Security Advisory (SSA-898115):** hxxps[://]cert-portal[.]siemens[.]com/productcert/pdf/ssa-898115[.]pdf