Vulnerability identifier: #VU8071

Vulnerability risk: Low

CVSSv3.1: 4.8 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:P/RL:O/RC:C]

CVE-ID: CVE-2017-12069

CWE-ID: CWE-611

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
SIMATIC NET PC Software
Server applications / SCADA systems
SIMATIC PCS 7
Server applications / SCADA systems
Siemens SIMATIC WinCC
Server applications / SCADA systems
SIMATIC WinCC Runtime Professional
Server applications / SCADA systems
SIMATIC IT Production Suite
Server applications / SCADA systems

Vendor: Siemens

Description
The vulnerability allows a remote attacker to conduct XXE attack on the target system.

The weakness exists in the encryption library due to improper handling of XML External Entity (XXE) entries when parsing an XML file. A remote attacker can send specially crafted packets to the OPC Discovery Server at Port 4840/TCP and cause the system to access various resources chosen by the attacker.

Successful exploitation of the vulnerability may result in information disclosure.

Mitigation
Install update from vendor's website.

Vulnerable software versions

SIMATIC NET PC Software: All versions

SIMATIC PCS 7: 7.1 - 8.1

Siemens SIMATIC WinCC: 7.0 - 7.4

SIMATIC WinCC Runtime Professional: 13.0 - 14.0

SIMATIC IT Production Suite: All versions

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External links
http://www.siemens.com/cert/pool/cert/siemens_security_advisory_ssa-535640.pdf

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.