Siemens S7-1200 Web Application Cross Site Scripting
Low RiskICS-CERT ICSA-12-283-01Jul 13, 2012
Summary
The SIMATIC S7-1200 PLC contains a cross-site scripting (XSS) vulnerability in its web application interface. An attacker can inject malicious JavaScript code through the web interface that executes in the context of an authenticated user's browser session. This vulnerability affects S7-1200 firmware versions V2.x, V3.0.0, and V3.0.1. Siemens has not released a patch for any of these versions.
What this means
What could happen
An attacker with network access to the S7-1200's built-in web interface could inject malicious code that executes in the browser of an engineer or operator accessing the PLC remotely, potentially allowing theft of credentials or session hijacking.
Who's at risk
Manufacturing facilities operating SIMATIC S7-1200 PLCs (V2.x, V3.0.0, V3.0.1) that use the PLC's built-in web interface for remote monitoring or configuration are at risk. This affects any organization relying on web-based access to these controllers for maintenance or diagnostics.
How it could be exploited
An attacker sends a crafted URL or tricks an authorized user into clicking a link containing JavaScript payloads. When the engineer or operator accesses the PLC's web interface through that link, the malicious script runs in their browser with their privileges, potentially capturing credentials or session tokens used to manage the PLC.
Prerequisites
- Network access to the S7-1200 web application interface (HTTP/HTTPS port)
- Ability to craft and deliver a malicious link to an authorized user who will click it
- User must authenticate to the PLC's web interface to be affected
no patch availableremotely exploitableaffects industrial control systems
Exploitability
Moderate exploit probability (EPSS 1.2%)
Affected products (3)
3 EOL
ProductAffected VersionsFix Status
SIMATIC S7-1200 PLC: V2.xV2.xNo fix (EOL)
SIMATIC S7-1200 PLC: V3.0.0V3.0.0No fix (EOL)
SIMATIC S7-1200 PLC: V3.0.1V3.0.1No fix (EOL)
Remediation & Mitigation
0/4
Do now
0/3HARDENINGRestrict network access to the S7-1200 web interface using firewall rules; allow only trusted engineering workstations and block public internet access
WORKAROUNDDisable the built-in web server on the S7-1200 if remote web-based management is not required
HARDENINGUse a VPN or jump host (bastion server) for all remote access to PLC web interfaces rather than direct internet exposure
Mitigations - no patch available
0/1The following products have reached End of Life with no planned fix: SIMATIC S7-1200 PLC: V2.x, SIMATIC S7-1200 PLC: V3.0.0, SIMATIC S7-1200 PLC: V3.0.1. Apply the following compensating controls:
HARDENINGEducate operators and engineers to avoid clicking untrusted links to PLC interfaces and to verify URLs before login
CVEs (1)
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