Secure Network - Security Research Advisory Vuln name: Philips VOIP841 Multiple Vulnerabilities Systems affected: Philips VOIP841, Firmware Version and, Web Server Version 1.5 (simple httpd) Systems not affected: n/a Severity: High Local/Remote: Remote Vendor URL: Author(s): Luca "ikki" Carettoni - Vendor disclosure: 23rd January 2008 Vendor acknowledged: - Vendor patch release: - Public disclosure: 14th February 2008 Advisory number: SN-2008-01 Advisory URL:, *** 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 80 Trying Connected to Escape character is '^]'. GET /../../../../../../../../etc/passwd HTTP/1.0 Host: 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/ HTTP/1.0 Host: 404 File Not Found httpd server: The requested URL '/var/htdocs/' was not found on this server. (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 ********************* *** LEGAL NOTICES *** ********************* Secure Network ( is an information security company, which provides consulting and training services, and engages in security research and development. 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