Denial of service in Siemens SIMATIC S7-400 CPUs

Published: 2018-05-16

Risk	Low
Patch available	YES
Number of vulnerabilities	1
CVE-ID	CVE-2018-4850
CWE-ID	CWE-20
Exploitation vector	Network
Public exploit	Public exploit code for vulnerability #1 is available.
Vulnerable software Subscribe	SIMATIC S7-400 H Server applications / SCADA systems SIMATIC S7-400 Hardware solutions / Firmware
Vendor	Siemens

Security Bulletin

This security bulletin contains one low risk vulnerability.

1) Improper input validation

EUVDB-ID: #VU12761

Risk: Low

CVSSv3.1: 6.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2018-4850

CWE-ID: CWE-20 - Improper input validation

Exploit availability: No

Description

The vulnerability allows a remote attacker to cause DoS condition on the target system.

The weakness exists due to improper validation of S7 communication packets. A remote attacker can send a specially crafted S7 communication packet to a communication interface of the CPU and cause the core functionality of the CPU to crash.

Mitigation

Install update from vendor's website.

Vulnerable software versions

SIMATIC S7-400 H: 4.5

SIMATIC S7-400: 4.0 - 5.2

External links

http://cert-portal.siemens.com/productcert/pdf/ssa-914382.pdf

Q & A

Can this vulnerability be exploited remotely?

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

How the attacker can exploit this vulnerability?

The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.

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.