Change Bootstrap 3 Input Outer Glow

CSS-override.css

.form-control:focus {
  border-color: #FF0000;
  box-shadow: inset 0 1px 1px rgba(0, 0, 0, 0.075), 0 0 8px rgba(255, 0, 0, 0.6);
}

SASS-method.scss

//For Sass version of BS3 https://github.com/twbs/bootstrap/commit/73c048578dfce7c6d4e8c9d4fe6c6bd22b2ff9b2
// _variables.scss: ~line 208
//** Border color for inputs on focus
$input-border-focus:             #66afe9 !default;
//mixins/_forms.scss ~line 55
@mixin form-control-focus($color: $input-border-focus) {
  $color-rgba: rgba(red($color), green($color), blue($color), .6);
  &:focus {
    border-color: $color;
    outline: 0;
    @include box-shadow(inset 0 1px 1px rgba(0,0,0,.075), 0 0 4px $color-rgba);
  }
}