VAX, TCP/IP, and Thirty Years of the Same Trust Problem
A Japanese version of this is on Note . I build RoamSwitch , a network security app for Mac and Linux, on my own. Maybe it's this line of work, but every time I write about AI agents automating cyberattacks, I keep thinking back to 1992, the year I entered this industry. What I was looking at then and what I'm looking at now are supposedly different technologies entirely, yet they keep feeling…
In 1992, the speaker entered the computer security industry, working for a large US computer company's Japan office. They noticed that password protection had taken two separate paths - VAX running VMS used a 32-bit hash based on an AUTODIN-II CRC, while HP-UX used a DES-based hash through crypt(3) with a 12-bit salt. The VMS password protection was introduced in 1978, while HP-UX adopted its approach in 1980.
However, both systems had significant weaknesses. HP-UX's trusted host mechanism, built on rlogin and .rhosts / hosts.equiv, was a major issue as trust was determined by hostname, which could be easily spoofed. The TCP/IP protocol, designed to connect different networks in 1974, did not include authentication or encryption, assuming a trusting research community.
The VAX in question did not speak TCP/IP natively; VMS used DECnet, and HP-UX incorporated TCP/IP from 4.2BSD since 1983. In 1985, Robert Morris Sr. documented a weakness in the 4.2BSD UNIX TCP/IP software, revealing that TCP sequence numbers were predictable, allowing an attacker to impersonate a trusted host. His son, Robert Tappan Morris, released the Morris Worm in 1988, exploiting sendmail's DEBUG mode, a buffer overflow in fingerd, and trust abuse through .rhosts / hosts.equiv, among other methods.
The worm infected roughly 6,000 systems, leading to the creation of CERT/CC at Carnegie Mellon to address computer security incidents.
Written by urgent.news from Dev.to's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
