Perl奇怪的源代码

Question

我找到了非正常运行的非字母数字perl代码!代码的开头:

eval eval '"'.
('!'^'+').'#'.('`'^'!').('['^'.').('['^'/').('`'|'(').('`'|'/').('['^')').':'.('{'^'/').('['^"\,").(
'`'|'%').('`'|'.').('['^'/').('['^'"').('`'^'/').('`'|'.').('`'|'%').('!'^'+').'#'.('`'^'$').(('`')|
'!').('['^'/').('`'|'%').':'.('`'^'!').('['^'.').('`'|"'").('['^'.').('['^'(').('['^'/').('{'^'[')

和这里的在引擎收录的文件.那怎么会发生:D

Answer 1

注意双字符串eval.最右边的eval解释所有("["^"/")类型的片段并将它们连接在一起.最左边的eval运行由最右边的eval解释产生的字符串.

每个(大多数)小的(....)片段占用一个字符并执行按位操作,例如xor和or另一个字符.因此,例如,("["^"/")成为单个字符't'.这与串联相结合构建了一个字符串,该字符串是实际可运行的Perl代码(如果您解开第一个(最右侧)eval,这看起来会更加明智).事实上,很容易看出真正的代码是什么样的.只需将最左侧的' eval'替换为' print',您就会看到最右侧eval的代码如何转换代码.

这是输出:

#Author:TwentyOne
#Date:August 21, 1969
#Title:md5bf.pl
#Description:Generates MD5 checksums provided by brute_keyword and then testing itself against the supplied hashster
#Contact <<<<<removed in SO post>>>>>
$speed = "1";

if ($speed<=0)
{ 
die "Set the speed equal or greater than one.\n";
}

use Digest::MD5 qw(md5_hex);
use Time::HiRes qw(gettimeofday);

if ($ARGV[0] =~"new") {
system('clear');
print "Enter a string\n";
print ">";
chomp(my $ask = <STDIN>);
system('clear');
system("echo -n '$ask' | md5sum\n");
exit(1);
}

if ($ARGV[0]=~"l") {
 $brute = "abcdefghijklmnopqrstuvwxyz";}
if ($ARGV[0]=~"u") {
 $brute = $brute. "ABCDEFGHIJKLMNOPQRSTUVWXYZ";}
if ($ARGV[0]=~"n") {
 $brute = $brute."1234567890";}
if ($ARGV[0]=~"x") {
 $brute = $brute. "!\"\$%&/()=?-.:~\\*'-_:.;,";}
if ($ARGV[0]=~"lu") {
 $brute = $brute. "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";}
if ($ARGV[0]=~"ln") {
 $brute = $brute. "abcdefghijklmnopqrstuvwxyz1234567890";}
if ($ARGV[0]=~"un") {
 $brute = $brute. "ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";}
if ($ARGV[0]=~"all") {
 $brute = $brute. "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!\"\$%&/()~=?-.:\\*'-_:.;,1234567890";}

if (! $ARGV[0]) {
usage();
exit(1);
}
if (! $ARGV[1]) {
usage();
exit(1);
}
if (! $ARGV[2]) {
usage();
exit(1);
}
if (! $ARGV[3]) {
usage();
exit(1);
}

if ($ARGV[3]) { 
    if (length($ARGV[3]) != 32) {
    print "MD5 Is Not Valid\n";
    sleep(1);
    system('clear');
    exit(1);
    }
}

if ($ARGV[0]=~"all") { 
print "Starting to Crack '$ARGV[3]'...\n";
sleep(2);
}else{
print "Starting to Crack '$ARGV[3]'...\n";
sleep(2);
}

for (my $bfv=$ARGV[1];$bfv<=$ARGV[2];$bfv++){
 crack ($bfv);
}

sub usage{
system('clear');
print '

????????????    ???????????????   ???????????????   ??? ??????? ????   ???????????\'s MD5 BRUTEFORCER
????????????    ????????????????  ???????????????? ??????????????????  ???????????
   ???   ??? ?? ?????????  ?????? ???   ???    ??????? ???   ????????? ?????????  
   ???   ????????????????  ??????????   ???     ?????  ???   ???????????????????  
   ???   ????????????????????? ??????   ???      ???   ???????????? ??????????????
   ???    ???????? ???????????  ?????   ???      ???    ??????? ???  ?????????????
';

print "\nUsage: perl $0 (brute_char) MIN_CHAR MAX_CHAR MD5 (options)" . "\n";
print "Ex) perl $0 all 1 5 865c0c0b4ab0e063e5caa3387c1a8741" . "\n";
print "brute_char // options;
all |   ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!\"\$%&/()~=?-.:\\*'-_:.;,1234567890
-
l   |   abcdefghijklmnopqrstuvwxyz
-
u   |   ABCDEFGHIJKLMNOPQRSTUVWXYZ
-
n   |   1234567890
-
x   |   !\"\$%&/()=?-.:~\\*'-_:.;,
-
lu  |   ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz
-
ln  |   abcdefghijklmnopqrstuvwxyz1234567890
-
un  |   ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890
---
new |   Generates MD5 Hash
-
v   |   Verbose (print output)
";
}

sub crack{
 $CharSet = shift;
 @RawString = ();
 for (my $i =0;$i<$CharSet;$i++){ $RawString[i] = 0;}
 $Start = gettimeofday();
 do{
  for (my $i =0;$i<$CharSet;$i++){
   if ($RawString[$i] > length($brute)-1){
    if ($i==$CharSet-1){
    print "Bruteforce finished, no results with $CharSet charachters. \n";
    $count=0;
    return false;
   }
   $RawString[$i+1]++;
   $RawString[$i]=0;
   }
  }

   $ret = "";
   for (my $i =0;$i<$CharSet;$i++){ $ret = $ret . substr($brute,$RawString[$i],1);}
   $hash = md5_hex($ret);
   $count++;
   $Stop = gettimeofday();
   if ($Stop-$Start>$speed){
    $count = int($count/$speed);
    $count=0;
    $Start = gettimeofday();
}

if ($ARGV[4] =~ 'v') { 
print "$ARGV[3] != $hash ($ret)\n";
}

   if ($ARGV[3] eq $hash){
    print "\n[+] MD5 Cracked! => $ret\n";
    exit(1);
   }
  $RawString[0]++;
 }while($RawString[$CharSet-1]<length($brute));
}

我想知道日期字段在顶部评论中的重要性.MD5算法于1992年首次发布,当然Perl 5甚至在1994年才发布.可能是作者的出生日期？他的联系信息是可用的(虽然我已经从这里发布的翻译代码中删除了它;你必须自己翻译才能获得它).

谷歌搜索日期并未发现可能适用的任何内容,因此我想要求作者解开这一部分的谜团.