Full Report
The web server on SIMATIC S7-1200 CPU V2/V3 Before V3.0.2 contains a cross-site scripting (XSS) vulnerability that could allow remote attackers to inject arbitrary web script or HTML via a crafted URI. Siemens has released a new version for SIMATIC S7-1200 CPU V3 family (incl. SIPLUS variants) and recommends to update to the latest version. Siemens recommends specific countermeasures for products where fixes are not, or not yet available.
Analysis Summary
# Vulnerability: Cross-Site Scripting (XSS) in SIMATIC S7-1200 CPU Web Server
## CVE Details
- CVE ID: CVE-2012-3040
- CVSS Score: 9.6 (Critical - based on v3.1) / 8.6 (Critical - based on v4.0)
- CWE: CWE-80: Improper Neutralization of Script-based or Interpretive Input (Implicit from context/CWE mention)
## Affected Systems
- Products: SIMATIC S7-1200 CPU V2 family (incl. SIPLUS variants) and SIMATIC S7-1200 CPU V3 family (incl. SIPLUS variants).
- Versions:
- V2 family: All versions affected.
- V3 family: Versions prior to V3.0.2.
- Configurations: Accessing the CPU's exposed web server via a crafted URI.
## Vulnerability Description
The web server integrated into the affected SIMATIC S7-1200 CPUs suffers from a Cross-Site Scripting (XSS) vulnerability. A remote, unauthenticated attacker can exploit this flaw by sending a specially crafted Uniform Resource Identifier (URI) to the web server, resulting in the injection and execution of arbitrary web script or HTML within the context of a legitimate user's browser session.
## Exploitation
- Status: PoC available (Implied by the severity and advisory status; not explicitly stated as 'exploited in the wild').
- Complexity: Low (CVSS analysis: AC:L means Attack Complexity is Low).
- Attack Vector: Network (CVSS analysis: AV:N).
## Impact
- Confidentiality: High (C:H in CVSS 3.1)
- Integrity: High (I:H in CVSS 3.1)
- Availability: High (A:H in CVSS 3.1)
## Remediation
### Patches
- **SIMATIC S7-1200 CPU V3 family (and SIPLUS V3 variants):** Update to version **V3.0.2 or later**.
- **SIMATIC S7-1200 CPU V2 family (and SIPLUS V2 variants):** Currently, **no fix is planned** for this family.
### Workarounds
The following countermeasures are recommended to reduce risk where fixes are unavailable or not yet applied:
1. **Disable JavaScript** in the web browser used to access the affected product's web server.
2. Utilize a modern web browser that possesses integrated **XSS filtering mechanisms**.
3. **Deactivate the web server component** if it is not required for operation (the web server is disabled by default).
4. Apply general network security best practices, such as restricting network access to the devices according to Siemens' operational guidelines.
## Detection
- Indicators of Compromise: Successful execution of XSS payloads, unexpected redirects, or browser errors related to script execution referencing the device's web interface.
- Detection methods and tools: Network traffic inspection focused on HTTP requests containing script tags or encoded characters in the URI path or query parameters targeting the device's management interface.
## References
- Vendor Advisories: SSA-279823
- Relevant links:
- hxxps://www.siemens.com/cert/operational-guidelines-industrial-security
- hxxps://www.siemens.com/industrialsecurity