ThinkPHP框架5.0.x SQL注入分析 & 数据库配置泄露
应用范围
开启debug模式的thinkphp5.0.x
漏洞复现
从官网上下载5.0.9完整版
application/index/controller/index.php内容如下
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| <?php
namespace app\index\controller;
use app\model\Gather;
class Index
{
public function index()
{
$ids = input('ids/a');
$t = db("user");
$result = $t->where('id', 'in', $ids)->select();
}
}
|
漏洞分析
我们在漏洞的关键位置下个断点进行分析,thinkphp\library\think\db\Builder.php:383行
调用堆栈为:
从index()方法开始
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| public function index()
{
$ids = input('ids/a');
$t = db("user");
$result = $t->where('id', 'in', $ids)->select();
}
|
调用$t->where('id', 'in', $ids)返回值的select()方法
我们先看下select()方法,它会将$option作为参数调用Builder::select方法
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| public function select($data = null)
{
...
$options = $this->parseExpress();
...
if (!$resultSet) {
$sql = $this->builder->select($options);
...
}
...
}
|
我们跟进$this->parseExpress();看$option是如何生成的
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| protected function parseExpress()
{
$options = $this->options;
...
}
|
这里是直接令$options = $this->options;,而$this->options是$t->where('id', 'in', $ids)过程生成的
跟进去发现有这一条语句 $this->options['where'][$logic] = array_merge($this->options['where'][$logic], $where);,其中$where由$where[$field] = [$op, $condition, isset($param[2]) ? $param[2] : null];得到
获得$option的调用链为:
$result = $t->where('id', 'in', $ids)->select(); ( public function where($field, $op = null, $condition = null) ) => $this->parseWhereExp('AND', $field, $op, $condition, $param); => $where[$field] = [$op, $condition, isset($param[2]) ? $param[2] : null];
我们回到$this->builder->select($options);,现在我们知道$this->options['where'][$logic]是我们的可控位置
跟进去
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| public function select($options = [])
{
$sql = str_replace(
['%TABLE%', '%DISTINCT%', '%FIELD%', '%JOIN%', '%WHERE%', '%GROUP%', '%HAVING%', '%ORDER%', '%LIMIT%', '%UNION%', '%LOCK%', '%COMMENT%', '%FORCE%'],
[
$this->parseTable($options['table'], $options),
$this->parseDistinct($options['distinct']),
$this->parseField($options['field'], $options),
$this->parseJoin($options['join'], $options),
$this->parseWhere($options['where'], $options),
$this->parseGroup($options['group']),
$this->parseHaving($options['having']),
$this->parseOrder($options['order'], $options),
$this->parseLimit($options['limit']),
$this->parseUnion($options['union']),
$this->parseLock($options['lock']),
$this->parseComment($options['comment']),
$this->parseForce($options['force']),
], $this->selectSql);
return $sql;
}
|
这个$this->parseWhere($options['where'], $options)分支进入了关键的漏洞位置,此时$where可控
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| protected function parseWhere($where, $options)
{
$whereStr = $this->buildWhere($where, $options);
...
return empty($whereStr) ? '' : ' WHERE ' . $whereStr;
}
|
再跟进$this->buildWhere($where, $options),此时$where可控
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| public function buildWhere($where, $options)
{
if (empty($where)) {
$where = [];
}
if ($where instanceof Query) {
return $this->buildWhere($where->getOptions('where'), $options);
}
$whereStr = '';
$binds = $this->query->getFieldsBind($options['table']);
foreach ($where as $key => $val) {
$str = [];
foreach ($val as $field => $value) {
...
$field = is_string($field) ? $field : '';
$str[] = ' ' . $key . ' ' . $this->parseWhereItem($field, $value, $key, $options, $binds);
}
$whereStr .= empty($whereStr) ? substr(implode(' ', $str), strlen($key) + 1) : implode(' ', $str);
}
return $whereStr;
}
|
$whereStr .= empty($whereStr) ? substr(implode(' ', $str), strlen($key) + 1) : implode(' ', $str);这个生成了sql语句的where部分,其中$str是由 $str[] = ' ' . $key . ' ' . $this->parseWhereItem($field, $value, $key, $options, $binds);生成的,而参数$value[1]就是我们ids[1,updatexml(0,concat(0x7e,(database()),0x7e),1)]=123%23payload中的键值
跟进$this->parseWhereItem($field, $value, $key, $options, $binds);
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| protected function parseWhereItem($field, $val, $rule = '', $options = [], $binds = [], $bindName = null)
{
$key = $field ? $this->parseKey($field, $options) : '';
if (!is_array($val)) {
$val = ['=', $val];
}
list($exp, $value) = $val;
if(....){
...
} elseif (in_array($exp, ['NOT IN', 'IN'])) {
if ($value instanceof \Closure) {
$whereStr .= $key . ' ' . $exp . ' ' . $this->parseClosure($value);
} else {
$value = is_array($value) ? $value : explode(',', $value);
if (array_key_exists($field, $binds)) {
$bind = [];
$array = [];
foreach ($value as $k => $v) {
if ($this->query->isBind($bindName . '_in_' . $k)) {
$bindKey = $bindName . '_in_' . uniqid() . '_' . $k;
} else {
$bindKey = $bindName . '_in_' . $k;
}
$bind[$bindKey] = [$v, $bindType];
$array[] = ':' . $bindKey;
}
$this->query->bind($bind);
$zone = implode(',', $array);
} else {
$zone = implode(',', $this->parseValue($value, $field));
}
$whereStr .= $key . ' ' . $exp . ' (' . (empty($zone) ? "''" : $zone) . ')';
}
}
return $whereStr;
}
|
然后我们可以看到当in_array($exp, ['NOT IN', 'IN'])条件满足时,将会直接将我们payload中的键值直接拼接到sql语句中
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| foreach ($value as $k => $v) {
if ($this->query->isBind($bindName . '_in_' . $k)) {
$bindKey = $bindName . '_in_' . uniqid() . '_' . $k;
} else {
$bindKey = $bindName . '_in_' . $k;
}
$bind[$bindKey] = [$v, $bindType];
$array[] = ':' . $bindKey;
}
|
而$exp则由$result = $t->where('id', 'in', $ids)->select();中的'in'经过一系列操作后得到
但是这里只能进行没有子查询语句的sql报错注入
如果有子查询语句的话就会报SQLSTATE[HY000]: General error: 1105 Only constant XPATH queries are supported的错误
所以这个sql注入有点不行,但时sql报错会暴露数据库配置却是非常有用的
参考
https://zerokeeper.com/vul-analysis/thinkphp-framework-50x-sql-injection-analysis.html
https://www.leavesongs.com/PENETRATION/thinkphp5-in-sqlinjection.html
