Full Report
The CPCI85 firmware of SICAM A8000 CP-8031 and CP-8050 is affected by multiple vulnerabilities such as authenticated remote command injection, exposure of serial UART interface, and hard coded credentials (for UART login). Siemens has released updates for the affected products and recommends to update to the latest versions.
Analysis Summary
# Vulnerability: Multiple Flaws in Siemens SICAM A8000 CPCI85 Firmware
## CVE Details
- **CVE ID:** CVE-2023-33919
- **CVSS Score:** 7.2 (High)
- **CWE:** CWE-77 (Command Injection)
- **CVE ID:** CVE-2023-33920
- **CVSS Score:** 6.8 (Medium)
- **CWE:** CWE-798 (Use of Hard-coded Credentials)
- **CVE ID:** CVE-2023-33921
- **CVSS Score:** 6.8 (Medium)
- **CWE:** CWE-749 (Exposed Dangerous Method or Function)
## Affected Systems
- **Products:**
- CP-8031 MASTER MODULE (6MF2803-1AA00)
- CP-8050 MASTER MODULE (6MF2805-0AA00)
- **Versions:** All firmware versions prior to CPCI85 V05
- **Configurations:** Devices using the web interface or providing physical access to the UART serial interface.
## Vulnerability Description
The CPCI85 firmware is affected by three primary security flaws:
1. **Remote Command Injection:** The web management interface lacks sufficient server-side input sanitization. This allows an authenticated user with high privileges to execute arbitrary system commands as the root user.
2. **Hard-coded Credentials:** The device stores a hard-coded root password hash. This hash can be extracted and used to authenticate via the serial console.
3. **Exposed UART Interface:** The physical hardware exposes a serial UART interface that provides a login prompt. When combined with the hard-coded credentials or brute-force attacks, it grants full administrative access to the device.
## Exploitation
- **Status:** PoC Available (Indicated by CVSS "Exploit Code Maturity: Functional/Proven")
- **Complexity:** Low
- **Attack Vector:**
- **CVE-2023-33919:** Network (Remote)
- **CVE-2023-33920 / CVE-2023-33921:** Physical (Requires direct access to device hardware)
## Impact
- **Confidentiality:** High (Full access to system data and configuration)
- **Integrity:** High (Ability to modify firmware, logic, and system settings)
- **Availability:** High (Potential for device bricking or service interruption)
## Remediation
### Patches
Siemens recommends updating affected modules to the following version:
- **CPCI85 V05** or later.
- Download link: hxxps[:]//support[.]industry[.]siemens[.]com/cs/ww/en/view/109804985/
### Workarounds
- Protect network access using firewalls and segmentation to restrict access to the web interface.
- Implement physical security controls (locked cabinets/rooms) to prevent unauthorized UART interface access.
- Apply general security hardening according to Siemens operational guidelines.
## Detection
- **Indicators of Compromise:**
- Unusual administrative logins or configuration changes.
- Evidence of physical tampering with the master module casing (accessing UART pins).
- Web server logs showing suspicious characters (`;`, `|`, `&`, `$()`) in HTTP requests.
- **Detection methods and tools:**
- Monitor network traffic for unauthorized access to the RTU management IPs.
- Periodic integrity checks of firmware and configuration files.
## References
- **Vendor Advisory:** hxxps[:]//cert-portal[.]siemens[.]com/productcert/pdf/ssa-731916[.]pdf
- **Siemens Grid Security:** hxxps[:]//www[.]siemens[.]com/gridsecurity