[Full-disclosure] Vulnerability in Linux Kiss Server v1.2

[vashnukad vashnukad]

I have not yet notified the vendors.

--
Name: Vashnukad
e-mail: vashnukad at vashnukad.com
Site: http://www.vashnukad.com

> On 3/5/08, David Judais <david.judais at googlemail.com> wrote:
> > Why isn't there a patch?
> >
> > > From: vashnukad at vashnukad.com
> > >
> > Site: http://www.vashnukad.com
> >
> > Application: Linux Kiss Server v1.2
> >
> > Type: Format strings
> >
> > Priority: Medium
> >
> > Patch available: No
> >
> >
> > The Linux Kiss Server contains a format strings vulnerability that, if run
> > in foreground mode, can be leveraged for access. The vulnerability is
> > demonstrated in the code below:
> >
> > Function log_message():
> >
> > if(background_mode == 0)
> >
> > {
> >
> > if(type == 'l')
> >
> > fprintf(stdout,log_msg);
> >
> >
> > if(type == 'e')
> >
> > fprintf(stderr,log_msg);
> >
> > free(log_msg);
> >
> > }
> >
> >
> >
> >
> > Function kiss_parse_cmd():
> >
> >
> >
> > /* check full command name */
> >
> > if (strncmp(cmd, buf, cmd_len))
> >
> > {
> >
> > asprintf(&log_msg,"unknow command: `%s'", buf);
> >
> > log_message(log_msg,'e');
> >
> > goto error;
> >
> > }
> >
> > buf += cmd_len;
> >
> >
> >
> > So putting something like %n%n%n in 'buf' you can trigger the
> vulnerability.
> >
> >
> > --
> >
> > Name: Vashnukad
> >
> > E-mail: vashnukad at vashnukad.com
> >
> > Site: http://www.vashnukad.com
> >
> >
> >
> >
> > --
> >
> > Name: Vashnukad
> >
> > e-mail: vashnukad at vashnukad.com
> >
> > Site: http://www.vashnukad.com
> >
>