Full Report
SINEMA Server V14 improperly sanitizes certain SNMP configuration data retrieved from monitored devices. An attacker with access to a monitored device could perform a stored cross-site scripting (XSS) attack that may lead to arbitrary code execution with SYSTEM privileges on the application server. Siemens recommends to migrate to its successor product SINEC NMS V2.0 or later. Siemens recommends to apply specific countermeasures for products where updates are not, or not yet available.
Analysis Summary
# Vulnerability: Stored XSS leading to SYSTEM Code Execution in SINEMA Server V14 via SNMP Data
## CVE Details
- CVE ID: CVE-2023-35796
- CVSS Score: 8.3 (High)
- CWE: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
## Affected Systems
- Products: SINEMA Server
- Versions: V14 (All versions)
- Configurations: The vulnerability is triggered when retrieving certain SNMP configuration data from monitored devices.
## Vulnerability Description
SINEMA Server V14 improperly sanitizes specific SNMP configuration data received from devices it monitors. This flaw allows an attacker who has access to a monitored device to inject malicious scripts. When SINEMA Server processes this data, it results in a **Stored Cross-Site Scripting (XSS)** attack, which can ultimately lead to **arbitrary code execution** with **SYSTEM privileges** on the application server.
## Exploitation
- Status: PoC available (Implied via ZDI-CAN-19823, indicating structured disclosure)
- Complexity: Medium (Attack requires access to a monitored device and specific conditions related to the monitored data being processed by the server)
- Attack Vector: Network (The attacker needs access to the network segment where the monitored device resides, allowing them to compromise the device providing the malicious SNMP data.)
## Impact
- Confidentiality: High (Potential for system access can lead to data exfiltration)
- Integrity: High (Arbitrary code execution allows for system modification)
- Availability: High (Code execution with SYSTEM privileges can lead to system shutdown or complete compromise)
## Remediation
### Patches
- **No fix is planned** for SINEMA Server V14 as it has reached end-of-support.
- **Recommended Migration:** Migrate to the successor product **SINEC NMS V2.0 or later**.
### Workarounds
1. **Restrict Access:** Restrict network access to the SNMP servers/devices being monitored by the SINEMA Server.
2. Follow general Siemens Industrial Security operational guidelines.
## Detection
- **Indicators of Compromise (IoCs):** Not explicitly listed, but potential IoCs would involve unexpected outbound network connections from the SINEMA Server host or changes to system files that correspond to successful SYSTEM-level command execution.
- **Detection Methods:** Network monitoring to detect unauthorized SNMP data injection attempts or host-based monitoring for unusual process execution stemming from the SINEMA Server application.
## References
- Vendor Advisories: SSA-594373
- Relevant Links:
- Siemens Security Advisory Portal: hxxps://www[.]siemens[.]com/cert/productcert/html/ssa-594373[.]html
- Operational Guidelines: hxxps://www[.]siemens[.]com/cert/operational-guidelines-industrial-security
- General Security Info: hxxps://www[.]siemens[.]com/industrialsecurity
- CWE List: hxxps://cwe[.]mitre[.]org/