I think you are slightly confused about references. Taking the reference of a variable does not return its name (although this is a clever idea). Is this why you expect @attrs to contain qw(nam pwd uid ..)?

The name of a variable can be used as a "soft reference" (only when the referent is a symbol table variable and only when in no strict 'refs'). But think of it, not all scalar values even have names, and some have many! Because of this, taking a reference to any variable using the backslash operator creates a special "hard reference" scalar. When you print out something of this reference type, you get SCALAR(0x81717c4) (if the referent is a normal scalar). Perhaps consult perlreftut for more detailed info?

A better way to fill your hash the way you want is like this:

my @fields = qw/nam pwd uid gid dsc hom shl/;

while (<F>) {
  my %attrs;
     @attrs{@fields} = split /:/, $_;

  $password->{ $attrs{nam} } = \%attrs;
}
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Again, you'll need an explicit list of keys for the hash, as you can't extract the attribute names from the variables.