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Tape Up Your Camera … Now!

Prof Bill Buchanan OBE FRSE
2 min readJul 9, 2019

I spend a good deal of my time reviewing the security of software — mainly the cryptography parts these days. I could thus tell you some stories about bad practice, but I won’t.

But today I have seen one of the worst implementations of security, and where lazy developers have simplified something, in order to make things simple for themselves. . Often security is seen as secondary, and the Zoom zero-day vulnerability is one of the worst I have seen [here].

Basically, Zoom installs a Web server on your computer, and which runs on port 19421:

meuser@MacBook-Pro-3:~/Downloads$ lsof -i :19421COMMAND   PID         USER   FD   TYPE            DEVICE SIZE/OFF NODE NAME
ZoomOpene 632 meuser 7u IPv4 0xae3b325b7648aa7 0t0 TCP localhost:19421 (LISTEN)

An NMAP scan doesn’t pick it up:

meuser@MacBook-Pro-3:~/Downloads$ nmap 127.0.0.1Starting Nmap 6.40 ( http://nmap.org ) at 2019-07-09 11:52 BST
Nmap scan report for localhost (127.0.0.1)
Host is up (0.0047s latency).
Not shown: 994 closed ports
PORT STATE SERVICE
88/tcp open kerberos-sec
445/tcp open microsoft-ds
548/tcp open afp
631/tcp open ipp
1023/tcp open netvenuechat
49165/tcp open unknown

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Prof Bill Buchanan OBE FRSE
Prof Bill Buchanan OBE FRSE

Written by Prof Bill Buchanan OBE FRSE

Professor of Cryptography. Serial innovator. Believer in fairness, justice & freedom. Based in Edinburgh. Old World Breaker. New World Creator. Building trust.

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