"Hacking" the (Telekom) Zyxel GPON SFP module (PMG3000-D20B)
The SFP can be sourced very easily and is widely available in Germany.
TLDR
Checkout the three options for configuring your SFP.
1. WEB UI
- Configure the ethernet interface the SFP is in with the IP
10.10.1.2/24. - Port-forward the SFPs web interface to your local machine via SSH:
ssh -L 127.0.0.1:8080:10.10.1.1:80. - Access the web-interface on
http://localhost:8080, usernameadmin, password1234.
2. CLI (on the SFP)
Note: The PLOAM ID has to be HEX encoded, in case yours is a 10-character string, you can transform it using
python3 -c 'print(hex(". Omit the"))' 0xprefix.
- Configure the ethernet interface the SFP is in with the IP
10.10.1.2/24. - SSH into the module using
[email protected], passwordadmin. - Login into the CLI with user
admin, paddword1234. - Change the PLOAM/SLID/Installationskennung by entering following commands followed by a newline:
halpassword
3. CLI (remote)
Note: requires Python >= 3.8
NAME
zyxel_gpon_sfp.py --sfp_addr=http://10.10.1.1
SYNOPSIS
zyxel_gpon_sfp.py --sfp_addr=http://10.10.1.1 - COMMAND
COMMANDS
COMMAND is one of the following:
info
set_slid
set_sn
Motivation
My ISPs (Deutsche Telekom) FTTH offering uses on a GPON network and distributes ONUs with a 1G (or 2.5G Ethernet) for non-business customers. I intended to run the fiber directly into my Linux router (using one of the SFP+ ports). Looking at the business offerings building upon the same technology revealed SFPs distributed only business customers using the Digitalisierungsbox Premium 2. The mentioned SFP is made by Zyxel with the identifier PMG3000-D20B and sold as Digitalisierungsbox Glasfaser Modem (Telekom only sells it to business customers but it is available online for ~40 Euros).
Accessing the module
After reverse engineering (this time it has been a fzf through all files, not analysing the binaries) the firmware of Telekom Digitalisierungsbox 2, I've identified the IP address of the module being 10.10.1.1/24 based on a SQL statement with a comment:
-- BS-6456: remove marker 'RESERVED' from static IP used to access the SFP module
UPDATE Ip SET Name="" WHERE IpAddress="10.10.1.2" AND Interface="eth1" AND LogicalInterface="eth1";
Digging a bit further in plaintext SQL statements reveals the credentials.
-- ...
INSERT INTO SshConfiguration VALUES ( 1, 0, 5, 22, 'Access only for authorized persons!', 0, '' );
INSERT INTO SshUser VALUES ( 1, 0, 'admin', 'admin', 0 );
-- ...
INSERT INTO GPONConfig VALUES ( 1, 1, '10.10.1.1', 'admin', '1234', '', '' );
Well, let's give it a try. SSH access sounds like a charm and is confirmed by nmap:
[email protected] ~ % nmap 10.10.1.1
Starting Nmap 7.80 ( https://nmap.org ) at 2022-02-02 06:31 UTC
Nmap scan report for 10.10.1.1
Host is up (0.00079s latency).
Not shown: 998 closed ports
PORT STATE SERVICE
22/tcp open ssh
80/tcp open http
MAC Address: <redacted> (Zyxel Communications)
Nmap done: 1 IP address (1 host up) scanned in 4.15 seconds
Let's give it a try with ssh [email protected]:
#######################################################
# #
# Please login to CLI mode. Then You can do commands. #
# #
#######################################################
Entering character mode
Escape character is '^]'.
Login: admin
Password:
ZYXEL#
ZYXEL#
linuxshell Enter linux shell
show show
system
manufactory
config
mib
sf
log
timer
bsp
hal
igmp
omci
ssp
ZYXEL# show version
Project Name: TW2362H-CDEL
Client Product Name: GTO100I_SFP_ZYXEL
Internal Product Name: GTO100I_SFP_ZYXEL
Hardware Version: PMG3000-D20B
Boot Version: V1.0.0
Client Software Version: V1.0.0
Internal Software Version: V1.0.0
Build User: jiangyuanqi
Build Time: 2021-05-08 11:28:36
Build Method: export ONU=gto100i_sfp_zyxel && cd ../drv && make install && cd .. && make rootfs && make install
GIT Info: TW2362H-CDEL_lantiq98035/customize/TW2362H-CDEL_lantiq98035_general_20150131:e057bd83
ZYXEL#
So, we can get a linux shell, nice. My SFP is running a (very old) release of OpenWrt:
ZYXEL# linuxshell
BusyBox v1.19.4 (2014-06-30 12:00:02 CST) built-in shell (ash)
Enter 'help' for a list of built-in commands.
_______ ________ __
| |.-----.-----.-----.| | | |.----.| |_
| - || _ | -__| || | | || _|| _|
|_______|| __|_____|__|__||________||__| |____|
|__| W I R E L E S S F R E E D O M
-----------------------------------------------------
ATTITUDE ADJUSTMENT (Attitude Adjustment, 12.09_ltq)
-----------------------------------------------------
* 1/4 oz Vodka Pour all ingredients into mixing
* 1/4 oz Gin tin with ice, strain into glass.
* 1/4 oz Amaretto
* 1/4 oz Triple sec
* 1/4 oz Peach schnapps
* 1/4 oz Sour mix
* 1 splash Cranberry juice
-----------------------------------------------------
[email protected]:~# uname -a
Linux SFP 3.10.12 #2 Wed Jul 12 12:01:33 CST 2017 mips GNU/Linux
[email protected]:~#
Changing GPON Serial Number / PLOAM Password
ZYXEL# hal
Hal#
linuxshell Enter linux shell
show show HAL configuration
sn change ont parameters
password change ont password
set set ont parameters
to1 change ont to1 interval
to2 change ont to2 interval
berinterval change BER interval
sfthreshold change SF threshold
sdthreshold change SD threshold
tcont add tcont
no delete HAL item
gemport add HAL item
reset Reset all pon configurations
get get
omci omci
stream stream
mvlanaction mvlanaction
uni PPTP UNI configuration
mtu MTU R/W
multicast multicast configartion
iphost iphost
init init
deny deny
permit permit
monitor monitor
mac mac
storm storm
print print
igmp igmp
mcastfilt McastFilt
Hal# sn
change ont serial number
Hal# password
Formate:XXXXXXXXXXXXXXXXXXXX
The password seems to consist of 10 bytes, entered hex encoded. This is likely the PLOAM password / SLID / Installationskennung / whatever you'd like to call it. The sn seems to change the serial number of the ONU (ONT) itself, I did not test that so far.
I assumed the CLI is using the configuration interface of OpenWRT under the hood; turns out I was right:
uci show gpon
gpon.ploam=gpon
gpon.ploam.nPassword=0x20 0x20 0x20 0x20 0x20 0x20 0x20 0x20 0x20 0x20
gpon.ploam.nT01=16000
gpon.ploam.nT02=100
gpon.ploam.nEmergencyStopState=0
gpon.ploam.nRogueMsgIdUpstreamReset=255
gpon.ploam.nRogueMsgRepeatUpstreamReset=3
gpon.ploam.nRogueMsgIdDeviceReset=255
gpon.ploam.nRogueMsgRepeatDeviceReset=3
gpon.ploam.nRogueEnable=0
gpon.gtc=gpon
gpon.gtc.bDlosEnable=0
gpon.gtc.bDlosInversion=0
gpon.gtc.nDlosWindowSize=0
gpon.gtc.nDlosTriggerThreshold=0
gpon.gtc.ePower=0
gpon.gtc.nLaserGap=0
gpon.gtc.nLaserOffset=0
gpon.gtc.nLaserEnEndExt=0
gpon.gtc.nLaserEnStartExt=0
gpon.gtc.nDyingGaspHyst=0
gpon.gtc.nDyingGaspMsg=0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
gpon.gtc.nDyingGaspEnable=0
gpon.ethernet=gpon
gpon.ethernet.bUNI_PortEnable0=1
gpon.ethernet.bUNI_PortEnable1=1
gpon.ethernet.bUNI_PortEnable2=1
gpon.ethernet.bUNI_PortEnable3=1
gpon.gpe=gpon
gpon.gpe.nPeNumber=6
Observing the GPON SN and Password in real time.
Serial and Password
The onu command helps debugging the system:
onu gtcpg: Retrieve passwordonu gtcsng: Retrieve serial number
Connection state
Connected (curr_state=5)
[email protected]:~# onu ploamsg
errorcode=0 curr_state=5
Disconnected (curr_state=1):
[email protected]:~# onu ploamsg
errorcode=0 curr_state=1 previous_state=0 elapsed_msec=16907701
HTTP API
Only after getting SSH access I discovered the SFP comes with a WebUI and a sort of API. The CLI zyxel_gpon_sfp.py makes use of this API to remotely configure the PLOAM password and possibly SN (again, didn't check it).
TODO
- Prometheus exporter
- Integrate into OpenWRT
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