Schneider Electric released an update to mitigate an improper input validation vulnerability in its ClearSCADA product, according to a report with ICS-CERT.
Successful exploitation of this remotely exploitable vulnerability, discovered by Sergey Temnikov and Vladimir Dashchenko of Kapersky Lab’s Critical Infrastructure Defense Team who reported the vulnerability to Schneider Electric, could cause the ClearSCADA server process and communications driver processes to terminate.
The following supported versions of ClearSCADA, server and communications driver processes, suffer from the issue:
• ClearSCADA 2014 R1 (build 75.5210) and prior
• ClearSCADA 2014 R1.1 (build 75.5387) and prior
• ClearSCADA 2015 R1 (build 76.5648) and prior
• ClearSCADA 2015 R2 (build 77.5882) and prior
ClearSCADA sees action in the critical manufacturing sector around the world.
No known public exploits specifically target this vulnerability. However, an attacker with a low skill level could exploit the vulnerability.
In the vulnerability, an attacker with network access to the ClearSCADA server can send specially crafted sequences of commands and data packets to the ClearSCADA server that can cause the ClearSCADA server process and ClearSCADA communications driver processes to terminate.
CVE-2017-6021 is the case number assigned to this vulnerability, which has a CVSS v3 base score of 7.5.
Schneider Electric released the following updates to mitigate the vulnerability:
• ClearSCADA 2014 R1.1 hotfix build 75.6239
• ClearSCADA 2015 R1.1 Service Pack (build 76.6191)
• ClearSCADA 2015 R2 hotfix build 77.6181
Users of ClearSCADA 2013 R2 and prior versions should upgrade to the latest ClearSCADA 2015 R2 hotfix to mitigate the vulnerability.
Each of the Service Pack and hotfixes above are available for direct download from Schneider Electric’s web site.
More information can be found by visiting Schneider Electric’s Security Notification.
Paris, France-based Schneider Electric recommends users include the following measures in their SCADA strategies:
• Secure physical and network interfaces to the ClearSCADA system
• Deploy suitably configured firewalls between network segments to limit access to ports and protocols appropriately
• Deploy VPN technology with secure authentication on any externally accessible networks
• Configure and audit user security to reduce the risk of a denial of service
• For critical accounts use ClearSCADA security policy configuration to disable invalid logon count and delayed lockout time and to use logon throttling