Re: [ANNOUNCE] DigSig 0.2: kernel module for digital signature verification for binaries

viro
2003-10-01T14:17:28Z

On Wed, Oct 01, 2003 at 09:33:09AM -0400, Makan Pourzandi wrote:

> Third, the intruder now has access to the system, he cannot execute the
> code he brought in with himself (not signed) or he cannot bring it in
> (c.f. above). So he needs to compile the code on the system. AFAIK, for
> the absolute majority of servers the admins remove all compilers
> (specially gcc) on all servers. this is for several different security
> reasons (I don't want to get there). therefore, the above hypothesis
> gets even more difficult to realize.

Don't be ridiculous. It's trivial to exploit a local buffer overrun in
one of your signed binaries and have the shellcode mmap the rest. All
pre-built, of course.

> Last, but I believe the most important, the level of difficulty of
> execution of such an attack is much higher than the average knowledge
> level of many script kiddies. The absolute majority of attackers have
> little or absolutely not any knowledge of the operating systems in
> general and linux in particular, let aside the knowledge of writing a C
> program, calling mmaps in that progam and run the malicious code to gain
> access as root, then remove the module to execute a classical attack.
>
> There is no such thing as 100% secure system, digsig increases the level
> of security of the system as it just makes it much more difficult for
> the intruder to succeed in his/her attack.

Rubbish. You don't need to compile anything locally and the rest will be
done once by some wanker with half a clue and then repeated by wankers
without a clue (aka script kiddies).