Security Advisory: An attacker could cause the device to go into defect mode, effectively causing a DoS, if specially crafted packets are sent to Port 443/TCP (HTTPS).
                                                                                
Author: Ralf Spenneberg <ralf@spenneberg.net>, Hendrik Schwartke, Maik Brüggemann
                                                                                
Revision: 1
                                                                                
Last Updated: March 21, 2014
                                                                                
CVE-2014-2258
                                                                                
Summary:
An attacker could cause the device to go into defect mode, effectively causing a DoS, if specially crafted packets are sent to Port 443/TCP (HTTPS). A cold restart is required to recover the system.

CVE-2014-2258e has been assigned to this vulnerability. A CVSS v2 base score of 7.8 has been assigned; the CVSS vector string is (AV:N/AC:L/Au:N/C:N/I:N/A:C).                                                                                
Impact:
Very High: A Cold Restart is required. 
CVSS: 7.8
                                                                                
                                                                                
Vulnerable:
All S7-1200 versions prior to V4.0
                                                                                        
                                                                                
Solution:
Workaround: Disabling the Webserver
Firmware 4.0

References:
https://ics-cert.us-cert.gov/advisories/ICSA-14-079-02
https://www.siemens.com/innovation/pool/de/forschungsfelder/siemens_security_advisory_ssa-654382.pdf