Local file inclusion vulnerability in Land Software - FAUST iServer


Local file inclusion vulnerability


Land Software - FAUST iServer

Vulnerable Version -

Fixed Version, Version 10

CVE Number







Mario Keck (Atos Germany)

The webserver called FAUST iServer developed by Land Software was found to be vulnerable to a local file inclusion vulnerability. An attacker is able to read all the local files of the underlying operating system in the context of the current hard drive where the iServer was installed.

Vendor description

(German) "Der FAUST iServer bringt Ihre FAUST- , FAUST Entry- und LIDOS-Datenbanken ins Intranet und Internet. Er bietet hohe Sicherheit und eine einfache Installation."

Source: www.land-software.de/lfs.fau

Business recommendation

The vendor provides a hotfix for the identified vulnerable versions. As the most actual version v10 of FAUST iServer is not vulnerable, no immediate action in the form of a patch is required. The webroot of the server should not be on the same partition as the operating system's root partition.

Vulnerability overview/description

1) Local File Inclusion (CVE-2021-34805)

When a URL is requested, the FAUST iServer checks for the corresponding ".fau" file on the operating system. ".fau" files can be compared with compiled webserver pages for displaying the content of the webpage. The identified vulnerable versions of FAUST iServer do not properly protect against a request aiming to read local files of the operating system.

FAUST iServer is designed to work on Windows operating systems only. Therefore, by simply URL-encoding a path like
..\..\..\windows\win.ini into %2e%2e%5c%2e%2e%5c%2e%2e%5cwindows%5cwin.ini
the FAUST iServer returns the contents of win.ini

Proof of concept

1) Local File Inclusion (CVE-2021-34805)

The following proof of concept shows the HTTP request that was used to read local files of the server's operating system. The vulnerability, as shown in the proof of concept request below, can be triggered as soon as a vulnerable version of FAUST iServer is in use. To read operating system specific files, the webroot of FAUST iServer has to be located on the same partition as the operating system root. Authorization is not needed.

HTTP Request:

GET /%5c%2e%2e%5c%2e%2e%5c%2e%2e%5c%2e%2e%5c%2e%2e%5c%2e%2e%5c%2e%2e%5c%2e%2e%5c%2e%2e%5c%2e%2e%5c%2e%2e%5c%2e%2e%5cwindows%5cwin.ini HTTP/1.1
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko
Connection: keep-alive
Host: <IP>
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8
Accept-Language: en-US,en;q=0.9


Vulnerable / tested versions

The following versions have been tested and found to be vulnerable:


Vendor contact timeline:

2021-06-10 Contacting vendor via email.
2021-06-14 Vendor requested more information about the vulnerability, which was provided on the same day.
2021-06-15 Requested information from vendor to check which versions are vulnerable.
2021-06-17 Vendor informed researcher about upcoming update and promised to inform all customers about the critical security fix in it.
2021-08-09 Confirmed the security fix in FAUST iServer
2021-08-16 Researcher received a notification mail from the vendor's newsletter announcing the official release of the fixed version.
2022-01-12 Version 10 was officially released and is available for all customers for upgrade.
2022-01-20 Release of security advisory


The vulnerability is fixed in the following version:


This patch should be immediately installed.

Version 10 is not affected by this vulnerability, if possible it is recommended to upgrade to this version.



Advisory URL



EOF Mario Keck (Atos Germany) / @2022

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