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

[vashnukad]

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
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