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mirror of https://github.com/hashcat/hashcat synced 2024-11-24 14:27:14 +01:00

m25400.pm take the user-password into account

This commit is contained in:
Your Name 2021-07-13 00:22:06 +02:00
parent b24ca10087
commit 012c5b16cd

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@ -86,7 +86,6 @@ sub pdf_compute_encryption_key_owner
my $R = shift;
my $enc = shift;
# TODO use user password as input for md5 of o_digest if no owner password is set
my $data;
$data .= $word;
$data .= substr ($padding, 0, 32 - length $word);
@ -110,7 +109,7 @@ sub pdf_compute_encryption_key_owner
}
else
{
$o_key = substr($o_digest, 0, 16); #length is always 128 bits or 16 bytes
$o_key = substr($o_digest, 0, 16); #length is always 128 bits or 16 bytes
}
#printf("\$o_key = %s\n", unpack ("H*", $o_key));
@ -127,6 +126,7 @@ sub module_generate_hash
my $V = shift;
my $R = shift;
my $enc = shift;
my $u_pass = shift;
if (defined $u == 0)
{
@ -173,45 +173,56 @@ sub module_generate_hash
################ USER PASSWORD #################
# do not change $u if it exists, keep this the same, as we don't know the user password,
# we cannot calculate this part of the hash again
if("".$u eq "0000000000000000000000000000000000000000000000000000000000000000")
my $res;
if("".$u_pass eq "")
{
my $res = pdf_compute_encryption_key_user($word, $padding, $id, $u, $o, $P, $V, $R, $enc);
my $digest = md5 ($padding . pack ("H*", $id));
my $m = Crypt::RC4->new ($res);
$u = $m->RC4 ($digest);
my @ress = split "", $res;
#do xor of rc4 19 times
for (my $x = 1; $x <= 19; $x++)
{
my @xor;
for (my $i = 0; $i < 16; $i++)
{
$xor[$i] = chr (ord ($ress[$i]) ^ $x);
}
my $s = join ("", @xor);
my $m2 = Crypt::RC4->new ($s);
$u = $m2->RC4 ($u);
}
$u .= substr (pack ("H*", $u_save), 16, 16);
$res = pdf_compute_encryption_key_user($word, $padding, $id, $u, $o, $P, $V, $R, $enc);
}
else
{
$u = pack("H*", $u)
#$u = pack("H*", $u)
#now that we know the user-password we can generate it
$res = pdf_compute_encryption_key_user($u_pass, $padding, $id, $u, $o, $P, $V, $R, $enc);
}
my $digest = md5 ($padding . pack ("H*", $id));
my $m = Crypt::RC4->new ($res);
$u = $m->RC4 ($digest);
my @ress = split "", $res;
#do xor of rc4 19 times
for (my $x = 1; $x <= 19; $x++)
{
my @xor;
for (my $i = 0; $i < 16; $i++)
{
$xor[$i] = chr (ord ($ress[$i]) ^ $x);
}
my $s = join ("", @xor);
my $m2 = Crypt::RC4->new ($s);
$u = $m2->RC4 ($u);
}
$u .= substr (pack ("H*", $u_save), 16, 16);
################ OWNER PASSWORD #################
my $o_key = pdf_compute_encryption_key_owner($word, $padding, $id, $u, $o, $P, $V, $R, $enc);
my $n = Crypt::RC4->new ($o_key);
$o = $n->RC4(substr ($padding, 0, 32 - length "")); # TODO dynamically add user password including padding to the RC4 input for the computation of the pdf o-value
if("".$u_pass eq "")
{
$o = $n->RC4(substr ($padding, 0, 32 - length ""));
}
else
{
#dynamically add user password including padding to the RC4 input for the computation of the pdf o-value
$o = $n->RC4($u_pass.substr ($padding, 0, 32 - length $u_pass));
}
#printf("padding_empty_str = %s\n", unpack ("H*", substr ($padding, 0, 32 - length "")));
my @ress2 = split "", $o_key;
@ -240,7 +251,15 @@ sub module_generate_hash
#printf("\$o = %s\n", unpack ("H*", $o));
#printf("\$u = %s\n", unpack ("H*", $u));
my $hash = sprintf ('$pdf$%d*%d*128*%d*%d*16*%s*32*%s*32*%s', $V, $R, $P, $enc, $id, unpack ("H*", $u), unpack ("H*", $o));
my $hash;
if("".$u_pass eq "")
{
$hash = sprintf ('$pdf$%d*%d*128*%d*%d*16*%s*32*%s*32*%s', $V, $R, $P, $enc, $id, unpack ("H*", $u), unpack ("H*", $o));
}
else
{
$hash = sprintf ('$pdf$%d*%d*128*%d*%d*16*%s*32*%s*32*%s*%s', $V, $R, $P, $enc, $id, unpack ("H*", $u), unpack ("H*", $o), $u_pass);
}
#print("hash\n".$hash."\n");
return $hash;
}
@ -256,7 +275,8 @@ sub module_verify_hash
my @data = split /\*/, $hash_in;
return unless scalar @data == 11;
my $i_data = scalar @data;
return unless ($i_data == 11) || ($i_data == 12); #or 12 if user-password is included
my $V = shift @data; $V = substr ($V, 5, 1);
my $R = shift @data;
@ -270,12 +290,18 @@ sub module_verify_hash
return unless (shift @data eq '32');
my $o = shift @data;
my $u_pass = "";
if($i_data == 12) {
$u_pass = shift @data;
#printf("u_pass = %s\n", $u_pass);
}
return unless defined $id;
return unless defined $word;
$word = pack_if_HEX_notation ($word);
my $new_hash = module_generate_hash ($word, $id, $u, $o, $P, $V, $R, $enc);
my $new_hash = module_generate_hash ($word, $id, $u, $o, $P, $V, $R, $enc, $u_pass);
return ($new_hash, $word);
}