($1,$2) = unpack 'x23 A15 x10 a10', $var;

##</code><code>##

$var =~ m[^.{23}(.{15}}.{10}(.{10})];

##</code><code>##

$1 = substr $var, 23, 15;
$2 = substr $var, 28, 10;

##</code><code>##

($1,$2) = unpack 'x23 a15 X10 a10', $var;                       

##</code><code>##

$var =~ m[(?=.{23}(.{15}))(?=.{28}(.{10}))];