Another TMTOWTDI, or ""Who need glob?"

#!/usr/bin/perl

use strict; # https://perlmonks.org/?node_id=11107038
use warnings;

my @lines = <DATA>;
@lines = map { /[^=:\s]*,[^=:\s]*/; map "$`$_$'", split /,/, $& } @lin
+es
  while "@lines" =~ /,/;
my %hash = split ' ', "@lines";
use Data::Dump 'dd'; dd \%hash;

__DATA__
Prefix1=A,B:c,d value1
Prefix2=A:b,c:1,2 value2
[download]

UPDATE: Should be :

#!/usr/bin/perl

use strict; # https://perlmonks.org/?node_id=11107038
use warnings;

my @lines = <DATA>;
@lines = map { /[^=:\s]*,[^=:\s]*/ ? map "$`$_$'", split /,/, $& : $_ 
+} @lines
  while "@lines" =~ /,/;
my %hash = split ' ', "@lines";
use Data::Dump 'dd'; dd \%hash;

__DATA__
Prefix1=A,B:c,d value1
Prefix2=A:b,c:1,2 value2
[download]