Resource exhaustion in Siemens products - CVE-2021-27385

Vulnerability identifier: #VU53146

CSH Severity: Medium

CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2021-27385

CWE-ID: CWE-400

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to application does not properly control consumption of internal resources. A remote attacker can send specially crafted packets to a SmartVNC device layout handler on the client side, trigger resource exhaustion and perform a denial of service (DoS) attack.

SIMATIC HMI Comfort Outdoor Panels 7” & 15”
SIMATIC HMI Comfort Panels 4”-22”
SIMATIC HMI KTP400F
SIMATIC HMI KTP700
SIMATIC HMI KTP700F
SIMATIC HMI KTP900
SIMATIC HMI KTP900F
SIMATIC WinCC Runtime Advanced

Install updates from vendor's website.

SIMATIC HMI Comfort Outdoor Panels 7” & 15” - update to 16 Update 4
SIMATIC HMI Comfort Panels 4”-22” - update to 16 Update 4
SIMATIC HMI KTP400F - update to 16 Update 4
SIMATIC HMI KTP700 - update to 16 Update 4
SIMATIC HMI KTP700F - update to 16 Update 4
SIMATIC HMI KTP900 - update to 16 Update 4
SIMATIC HMI KTP900F - update to 16 Update 4
SIMATIC WinCC Runtime Advanced - update to 16 Update 4

• https://ics-cert.us-cert.gov/advisories/icsa-21-131-12
• https://cert-portal.siemens.com/productcert/pdf/ssa-538778.pdf

• Multiple vulnerabilities in Siemens SIMATIC SmartVNC HMI WinCC Products