COMMAND
SecurID
SYSTEMS AFFECTED
Systems using SecurID
PROBLEM
Drew Dean found following. He had a SecurID card for my Princeton
Computer Science department account. The setup is that an old
Sun, running SunOS 4.1.4, is running the SecurID software; you
telnet to it, authenticate, and then rlogin to where you want to
go. While this setup isn't perfect, the router hooking these
machines to the outside world is setup to prevent spoofing, and
the local network is deemed to be under reasonable control.
While back, when he logged in, and tried to rlogin to the
workstation on my (former) desk. It said, "Not on system
console." Funny, it only says that if you attempt to rlogin as
root. Oops, a # prompt, and /usr/bin/id reported UID 0.
Further investigation yielded that our entries in /etc/passwd were
of the form +<username>:::::: i.e., to get our information from
NIS. However, due to a pending network reconfiguration, the
machine was temporarily not using NIS, and no ypbind was running.
It appears that the SecurID software didn't check the return
value, and used a default value of 0. (The SecurID software keeps
a separate database for its authentication information.) This
raises interesting questions about a denial of service attack
escalating to a root compromise (for local users; you need a
SecurID card to login with).
SOLUTION
Security Dynamics has been notified.