Memory leak in UltraVNC - CVE-2019-8259

Vulnerability identifier: #VU22961

CSH Severity: Medium

CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2019-8259

CWE-ID: CWE-401

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to gain access to sensitive information on the target system.

The vulnerability exists due memory leak in VNC client code. A remote attacker that controls a malicious VNC server can trick a user to connect to it and access sensitive information.

Combined with another vulnerability, it can be used to leak stack memory and bypass ASLR.

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

Install updates from vendor's website.

UltraVNC - update to 1.2.2.3
SIMATIC WinCC Runtime Advanced - update to 16 Update 4
SIMATIC HMI KTP900F - update to 16 Update 4
SIMATIC HMI KTP900 - update to 16 Update 4
SIMATIC HMI KTP700F - update to 16 Update 4
SIMATIC HMI KTP700 - update to 16 Update 4
SIMATIC HMI KTP400F - update to 16 Update 4
SIMATIC HMI Comfort Panels 4”-22” - update to 16 Update 4
SIMATIC HMI Comfort Outdoor Panels 7” & 15” - update to 16 Update 4

• https://ics-cert.kaspersky.com/advisories/klcert-advisories/2019/03/01/klcert-19-005-ultravnc-memory-leak/

• Multiple vulnerabilities in UltraVNC
• Multiple vulnerabilities in Siemens SIMATIC UltraVNC HMI WinCC Products