## Advisory Information

Title: Backdoor credentials found in 4 TOTOLINK router models
Advisory URL: https://pierrekim.github.io/advisories/2015-totolink-0x03.txt
Blog URL: https://pierrekim.github.io/blog/2015-07-16-backdoor-credentials-found-in-4-TOTOLINK-products.html
Date published: 2015-07-16
Vendors contacted: None
Release mode: 0days, Released
CVE: no current CVE



## Product Description

TOTOLINK is a brother brand of ipTime which wins over 80% of SOHO
markets in South Korea.
TOTOLINK produces routers routers, wifi access points and network
devices. Their products are sold worldwide.



## Vulnerabilities Summary

Backdoor credentials are present in several TOTOLINK products.

It affects 4 TOTOLINK products (firmwares come from totolink.net and
from totolink.cn):

G150R-V1 : last firmware 1.0.0-B20150330
(TOTOLINK-G150R-V1.0.0-B20150330.1734.web)
G300R-V1 : last firmware 1.0.0-B20150330
(TOTOLINK-G300R-V1.0.0-B20150330.1816.web)
N150RH-V1 : last firmware 1.0.0-B20131219
(TOTOLINK-N150RH-V1.0.0-B20131219.1014.web)
N301RT-V1 : last firmware 1.0.0 (TOTOLINK N301RT_V1.0.0.web)

It allows an attacker in the LAN to connect to the device using telnet
with 2 different accounts: root and 'onlime_r' which gives with root
privileges.



## Details - G150R-V1 and G300R-V1

The init.d script executes these commands when the router starts:

[...]
cp /etc/passwd_orig /var/passwd
cp /etc/group_orig /var/group
telnetd&
[...]


The /etc/passwd_orig contains backdoor credentials:

root:$1$01OyWDBw$Hrxb2t.LtmiiJD49OBsCU/:0:0:root:/:/bin/sh
onlime_r:$1$01OyWDBw$Hrxb2t.LtmiiJD49OBsCU/:0:0:root:/:/bin/sh
nobody:x:0:0:nobody:/:/dev/null

The corresponding passwords are:

root:12345
onlime_r:12345


## Details - N150RH-V1 and N301RT

The init.d script executes these commands when the router starts:

[...]
#start telnetd
telnetd&
[...]

The binary /bin/sysconf executes these commands when the router starts:

system("cp /etc/passwd.org /var/passwd 2> /dev/null")


The /etc/passwd.org contains backdoor credentials:

root:$1$01OyWDBw$Hrxb2t.LtmiiJD49OBsCU/:0:0:root:/:/bin/sh
onlime_r:$1$01OyWDBw$Hrxb2t.LtmiiJD49OBsCU/:0:0:root:/:/bin/sh
nobody:x:0:0:nobody:/:/dev/null

The corresponding passwords are:

root:12345
onlime_r:12345



## Vendor Response

TOTOLINK was not contacted in regard of this case.



## Report Timeline

* Jun 25, 2015: Backdoor found by analysing TOTOLINK firmwares.
* Jun 26, 2015: working PoCs.
* Jul 16, 2015: A public advisory is sent to security mailing lists.



## Credit

These backdoor credentials were found Pierre Kim (@PierreKimSec).



## References

https://pierrekim.github.io/advisories/2015-totolink-0x03.txt



## Disclaimer

This advisory is licensed under a Creative Commons Attribution Non-Commercial
Share-Alike 3.0 License: http://creativecommons.org/licenses/by-nc-sa/3.0/