VNC vulnerabilities. TigerVNC security update

[Pavel Cheremushkin <Pavel.Cheremushkin () kaspersky com>]

Hello,

This is a final report about reviewing open source VNC implementations. This research has been motivated by the fact 
that some VNC systems are heavily used in ICS.

About a year ago I have already sent an email to this mailing list about TightVNC and LibVNC vulnerabilities: 
https://www.openwall.com/lists/oss-security/2018/12/10/5
Later this year I had some time to review more open source implementations of VNC systems (mostly UltraVNC), which are 
described in this article: https://ics-cert.kaspersky.com/reports/2019/11/22/vnc-vulnerability-research/

Finally, today TigerVNC team managed to fix all issues found within their codebase and published fixes in new release 
1.10.1
https://github.com/TigerVNC/tigervnc/releases/tag/v1.10.1
https://github.com/TigerVNC/tigervnc/commit/d461f7fdb8b01f655260ea2f495ece700f3c9898

Fix contains patches for several vulnerabilities that have been fixed in master branch only, and 5 vulnerabilities 
(CVE-2019-15691 -- CVE-2019-15695) that actually got into the previous release. CVE-ids will published shortly. Please 
update.

Also, I accidently found another heap buffer overflow in LibVNC (CVE-2019-15690), when I was playing with CodeQL 
queries. It was missed during previous analysis by me. It later turned out that my fuzzer didn't find it either, 
because it required at least 256MB to be sent over the network to trigger it :)

Best Regards,
Pavel Cheremushkin
Security Researcher| ICS CERT Vulnerability Research Group | Kaspersky Lab
39A bld.2 Leningradskoye Highway, Moscow 125212, Russia | www.kaspersky.com,www.securelist.com