如何转换 Base64 字符串？

Question

我正在使用下载的 PHP 模板，当我熟练地操作它时，我意识到它的一部分已经以似乎是 base64 的方式加密了。

我尝试了一些在线转换，但运气不佳。

我有这段代码，后面是 标签：

<?$OOO0O0O00=__FILE__;$O00O00O00=__LINE__;$OO00O0000=3804;eval((base64_decode('JE8wMDBPME8wMD1mb3BlbigkT09PME8wTzAwLCdyYicpO3doaWxlKC0tJE8wME8wME8wMClmZ2V0cygkTzAwME8wTzAwLDEwMjQpO2ZnZXRzKCRPMDAwTzBPMDAsNDA5Nik7JE9PMDBPMDBPMD0oYmFzZTY0X2RlY29kZShzdHJ0cihmcmVhZCgkTzAwME8wTzAwLDM3MiksJzNzYWZaakc1NEhGcU1kTEFPZzl3Ykl6UFIvcGxLOCs3ZVVjeFFCV21ZMXVTNk5Ycmh2RENudDBFMlRvSmtWaXk9JywnQUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVphYmNkZWZnaGlqa2xtbm9wcXJzdHV2d3h5ejAxMjM0NTY3ODkrLycpKSk7ZXZhbCgkT08wME8wME8wKTs=')));return;?>

我能够将其解码为：

$O000O0O00=fopen($OOO0O0O00,'rb');while(--$O00O00O00)fgets($O000O0O00,1024);fgets($O000O0O00,4096);$OO00O00O0=(base64_decode(strtr(fread($O000O0O00,372),'3safZjG54HFqMdLAOg9wbIzPR/plK8+7eUcxQBWmY1uS6NXrhvDCnt0E2ToJkViy=','ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/')));eval($OO00O00O0);

但是，在下面我有以下代码：

http: //pastebin.com/Z2uMwS9C

我不知道如何转换它。有什么想法吗？我觉得代码段太长了 - 我尝试用Notepad++转换它，它基本上说它太长了。

谢谢。

Answer 1

这是我到目前为止所拥有的解压缩版本：

<?php
/* In the original file, this is __FILE__
   and __LINE__. I've hardcoded them in this
   script so that we can refer to the original
   file when actually running what follows. */
$this_file = 'original_file.php';
$this_line = 1; // originally __LINE__

/* Prepare the original script to be read */
$this_file_handle = fopen($this_file, 'rb');

/* Move the file cursor past the block of PHP */
while(--$this_line) {
  fgets($this_file_handle,1024);
}

/* Move the file cursor just a wee bit more,
   presumably to where the other data starts. */
fgets($this_file_handle,4096);

/* Read in the remaining data, run it through
   a character replacing function
   (3 --> A, s --> B, etc.), and base64-decode
   the result. */
$probably_malicious_code = (
  base64_decode(
    strtr(
      fread($this_file_handle,372),
      '3safZjG54HFqMdLAOg9wbIzPR/plK8+7eUcxQBWmY1uS6NXrhvDCnt0E2ToJkViy=',
      'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
    )
  )
);

/* Run the probably-evil code. */
eval($probably_malicious_code);

如果我们在最后一行使用 echo 而不是 eval，我们会得到第三级混淆。

INCEPTIO N

这是一个与第 3 级发生的情况等效的脚本：

<?php
/* Pulled in from level 1: */
$this_file = 'original_magic.php'; // originally __FILE__, refers to original file
$this_line = 1; // originally __LINE__
$level_three_read_amount = 3804;

/* Pulled in from level 2: */
$this_file_handle = fopen($this_file, 'rb');

while(--$this_line) {
  fgets($this_file_handle,1024);
}

fgets($this_file_handle,4096);

/* Level 3 decoding: */
$level_three_code = ereg_replace(
  '__FILE__',
  "'".$this_file."'", //
  base64_decode(
    strtr(
      fread($this_file_handle, $level_three_read_amount),
      '3safZjG54HFqMdLAOg9wbIzPR/plK8+7eUcxQBWmY1uS6NXrhvDCnt0E2ToJkViy=',
      'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/'
    )
  )
);

fclose($this_file_handle);
eval($level_three_code);

这次回显而不是评估最后一行会产生接近我们最终效果的东西：

global $traction; ;echo '   </div><!--end main-->
    <div id="main-bottom"></div>
</div><!--end wrapper-->
<div id="footer">
    <div class="wrapper clear">
        <div id="footer-about" class="footer-column">
            '; if ($traction->footerAboutState() == 'true') : ;echo '               <ul>
                    '; if ( !function_exists('dynamic_sidebar')|| !dynamic_sidebar('footer_sidebar_3') ) : ;echo '              <li class="widget widget_categories">
                            <h2 class="widgettitle">'; _e('Categories'); ;echo '</h2>
                            <ul>
                                '; wp_list_cats('sort_column=name&hierarchical=0'); ;echo '                 </ul>
                        </li>
                    '; endif; ;echo '           </ul>
            '; else : ;echo '               <h2>'; _e( 'About', 'traction' ); ;echo '</h2>
                '; if ($traction->footerAbout() != '' ) : ;echo '                   '; echo $traction->footerAbout(); ;echo '               '; else : ;echo '               <p>'; _e("Did you know you can write your own about section just like this one? It's really easy. Head into the the <em>Traction Options</em> menu and check out the footer section. Type some stuff in the box, click save, and your new about section shows up in the footer.", "traction"); ;echo '</p>
                '; endif; ;echo '           '; endif; ;echo '       </div>
        <div id="footer-middle" class="footer-column">
            '; if ( is_active_sidebar( 'footer_sidebar' ) ) echo "<ul>" ;echo '             '; if ( !function_exists( 'dynamic_sidebar' ) || !dynamic_sidebar( 'footer_sidebar' ) ) : ;echo '           <ul>
                        <li class="widget">
                            <h2 class="widgettitle">'; _e( 'Pages' ); ;echo '</h2>
                            <ul>
                                '; wp_list_pages( 'depth=0&title_li=' ); ;echo '                        </ul>
                        </li>
                    </ul>
                '; endif; ;echo '           '; if ( is_active_sidebar( 'footer_sidebar' ) ) echo "</ul>" ;echo '        </div>
        <div id="footer-search" class="footer-column">
            '; if ( is_active_sidebar( 'footer_sidebar_2' ) ) echo "<ul>" ;echo '               '; if ( !function_exists( 'dynamic_sidebar' ) || !dynamic_sidebar( 'footer_sidebar_2' ) ) : ;echo '         <h2>'; _e( 'Search', 'traction' ); ;echo '</h2>
                    '; if (is_file(STYLESHEETPATH . '/searchform.php' )) include (STYLESHEETPATH . '/searchform.php' ); else include(TEMPLATEPATH . '/searchform.php' ); ;echo '                '; endif; ;echo '           '; if ( is_active_sidebar( 'footer_sidebar_2' ) ) echo "</ul>" ;echo '      </div>
    </div><!--end wrapper-->
</div><!--end footer-->
<div id="copyright" class="wrapper">
    <p class="credit">Powered by <a href="http://www.free-premium-wordpress-themes.com" rel="dofollow">Free Premium Wordpress Themes</a> and <a href="http://thethemefoundry.com">The Theme Foundry</a></p>
    <p>Copyright © '; echo date

由于某种原因有点被切断，但它看起来这个想法只是包含版权，同时让你很难找到它。这是一件粗略的事情；删除此代码。