\"special\" shells a security hole?

[mouse at mcgill-vision.UUCP]

In article <2590002 at hpisod2.HP>, decot at hpisod2.HP (Dave Decot) writes:
> As long as it [a special `shell' with an escape to a real shell]
> doesn't run such programs as more(1) or ex(1), either, since they can
> be used to get someplace where a shell escape is available.

Except that the shell escaped to would be a copy of the special shell,
no?  This is certainly the case here with one program we have.  We have
an Ultrix system, which has a program dlogin to perform remote logins
over DECnet (don't ask why we're running DECnet, you don't want to
know).  We wanted a pseudo-user which just prompted for a hostname and
ran dlogin.  However, dlogin has a shell escape.  But when it's used,
all you get is another hostname prompt!

> In general, the fewer outside programs the application permits the
> user to use, the more secure such applications are.

This is pretty tough to argue with.

					der Mouse

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