openSIS <= 7.4 Incorrect Access Control Vulnerabilities

• Software Link:

https://opensis.com

• Affected Versions:

Version 7.4 and prior versions.

• Vulnerabilities Description:

The application prevents unauthenticated access to its functionalities by including the RedirectIncludes.php, RedirectModules.php, and RedirectRootInc.php scripts, which implement the access control logic by using the following code:

1if(!$_SESSION['STAFF_ID'] && !$_SESSION['STUDENT_ID'] && strpos($_SERVER['PHP_SELF'],'index.php')===false)
2{
3    header('Location: ../../../index.php');
4    exit;
5}

This can be easily bypassed by appending /index.php at the end of the URL, and can be exploited by unauthenticated attackers to potentially access any application functionality which should require the user to be authenticated.

• Solution:

No official solution is currently available.

• Disclosure Timeline:

[04/11/2019] – Vendor notified

[04/11/2019] – Vendor acknowledgement

[10/01/2020] – Vendor contacted again asking for updates

[15/01/2020] – Vendor replied they would need a few examples

[20/01/2020] – Told the vendor they could use the PoC I sent them in November

[05/02/2020] – Vendor asked for a video recording to demonstrate the vulnerabilities

[06/02/2020] – Proof of Concept video sent to the vendor

[03/03/2020] – Vendor contacted again asking for updates

[04/03/2020] – Vendor replied “we just have to wait a little longer”

[25/04/2020] – Version 7.4 released, vulnerabilities still not fixed

[22/05/2020] – CVE number assigned

[30/06/2020] – Public disclosure

• CVE Reference:

The Common Vulnerabilities and Exposures project (cve.mitre.org) has assigned the name CVE-2020-13382 to these vulnerabilities.

• Credits:

Vulnerabilities discovered by Egidio Romano.