I've tested this exploit in wrong way. I've first logged in as root, then I
made "su nobody" and then exploit worked.
If I don't login as root at the beginning, I get operation not permited.. so
kernel is safe after all :)
Thanks 4 your time
Best regards,
Bojan Pogacar
> Hello,
>
> I've upgraded my linux box to 2.4.21 because of the securety reasons. Now
I
> found out that old local expoloit for ptrace is stil working under 2.4.21.
> Wasn't it fixed in RC1?
>
> In attachment I send you exploit, which is still working!
>
>
> Best regards,
>
> Bojan Pogacar
>
On Sat, 14 Jun 2003, Bojan Pogaèar wrote:
> I've tested this exploit in wrong way. I've first logged in as root, then I
> made "su nobody" and then exploit worked.
Maybe "nobody" isn't a "real" user in your case. If there is some problem
with it, you may end up with uid 0 after "su nobody".
check the output of the command "id" after the executiong the su command,
just to be safe in any case!
If su really worked correctly, the exploit may not even work if you
su (successfully) su'ed from root.
Bernd
> If I don't login as root at the beginning, I get operation not permited.. so
> kernel is safe after all :)
>
> Thanks 4 your time
>
>
> Best regards,
>
> Bojan Pogacar
>
>
> > Hello,
> >
> > I've upgraded my linux box to 2.4.21 because of the securety reasons. Now
> I
> > found out that old local expoloit for ptrace is stil working under 2.4.21.
> > Wasn't it fixed in RC1?
> >
> > In attachment I send you exploit, which is still working!
> >
> >
> > Best regards,
> >
> > Bojan Pogacar
> >
>
Hi all.
>>> I've upgraded my Linux box to 2.4.21 because of the security
>>> reasons. Now I found out that old local exploit for ptrace
>>> is still working under 2.4.21. Wasn't it fixed in RC1?
>> I've tested this exploit in wrong way. I've first logged in as
>> root, then I made "su nobody" and then exploit worked.
> Maybe "nobody" isn't a "real" user in your case. If there is some
> problem with it, you may end up with uid 0 after "su nobody".
>
> check the output of the command "id" after the executing the su
> command, just to be safe in any case!
>
> If su really worked correctly, the exploit may not even work if
> you su (successfully) su'ed from root.
Probably more to the point, the command `su nobody` does NOT log you
in as user nobody. You need the command `su -l nobody` to do that.
Check the manpage for su to verify that without the -l option, you
are still logged in as user root although you are running with the
effective user nobody.
My understanding is that the permissions checks can succeed when
EITHER your login or effective user would succeed in most cases,
but in some cases, it's when your login user succeeds irrespective
of whether your effective user would succeed or not.
Best wishes from Riley.
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