Re: YA Apache DoS attack

From: bugtraq (bugtraqat_private)
Date: Sun Aug 09 1998 - 12:53:56 PDT

  • Next message: Julio Casal: "Re: Solaris 2.4 pop buffer overrun"

    >And here's a band-aid for 1.3.1 - I'm sure we'll come up with something better
    >soon. This (untested) patch should prevent the worst effects. A similar patch
    >should work for 1.2.x.
    
    A similar version of this patch works against Apache 1.2.5.  I have made
    RPMs for RedHat, Caldera, SuSE, TurboLinux, and other RPM-based systems
    available at this location:
    
            http://www.samiam.org/blackdragon
    
    Patch for Apache 1.2.5 included.  I have verified that this patch protects
    Apache 1.2.5 from the sioux DOS attack.
    
    - Sam
    
    *** apache_1.2.5/src/http_protocol.c.orig       Sun Aug  9 11:44:00 1998
    --- apache_1.2.5/src/http_protocol.c    Sun Aug  9 11:53:13 1998
    ***************
    *** 659,664 ****
    --- 659,665 ----
          int len;
          char *value;
          char field[MAX_STRING_LEN];
    +     int nheaders=0;
    
          /* Read header lines until we get the empty separator line,
           * a read error, the connection closes (EOF), or we timeout.
    ***************
    *** 674,679 ****
    --- 675,686 ----
              while (isspace(*value)) ++value;      /* Skip to start of value   */
    
              table_merge(r->headers_in, field, value);
    +
    +       if(++nheaders >= 100) {
    +           r->status = HTTP_BAD_REQUEST;
    +           return;
    +       }
    +
          }
      }
    



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