CVE-2017-5197 in SilverStripe
Summary
by MITRE
There is XSS in SilverStripe CMS before 3.4.4 and 3.5.x before 3.5.2. The attack vector is a page name. An example payload is a crafted JavaScript event handler within a malformed SVG element.
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Analysis
by VulDB Data Team • 09/04/2020
The vulnerability identified as CVE-2017-5197 represents a cross-site scripting flaw within the SilverStripe content management system that affects versions prior to 3.4.4 and 3.5.x prior to 3.5.2. This vulnerability specifically targets the handling of page names within the CMS interface, creating a potential attack vector that could be exploited by malicious actors to inject malicious scripts into the application's user interface. The flaw stems from insufficient input validation and sanitization of page name parameters, allowing attackers to craft malicious payloads that can execute within the context of other users' browsers when they interact with affected pages.
The technical implementation of this vulnerability involves the exploitation of JavaScript event handlers embedded within malformed svg elements that are processed as page names. This particular attack vector leverages the browser's interpretation of svg elements and their associated event handlers, which can be executed when the malformed content is rendered in the CMS interface. The vulnerability is classified under CWE-79 as a cross-site scripting issue, specifically involving the improper validation of input data that leads to the execution of malicious scripts in the victim's browser context. The attack requires the malicious actor to have the ability to create or modify page names within the CMS, which typically requires user privileges that could be gained through various means including credential compromise or other initial access vectors.
The operational impact of CVE-2017-5197 extends beyond simple script execution, as it can enable attackers to perform a wide range of malicious activities including session hijacking, data theft, and redirection to malicious websites. When users navigate to pages containing the crafted svg payloads, the JavaScript code embedded within the event handlers executes in their browser, potentially allowing attackers to steal cookies, session tokens, or other sensitive information. This vulnerability aligns with ATT&CK technique T1059.007 for scripting, specifically targeting the execution of malicious scripts through web-based interfaces. The impact is particularly concerning in CMS environments where administrators frequently interact with page names and content, as the attack can be executed with minimal user interaction beyond viewing the affected pages.
Organizations affected by this vulnerability should immediately implement the recommended security patches that were released as part of the SilverStripe 3.4.4 and 3.5.2 updates, which address the input validation issues in page name handling. Additional mitigations should include implementing robust content security policies that restrict the execution of inline scripts and restrict the types of characters allowed in page names. The vulnerability demonstrates the importance of proper input sanitization and output encoding in web applications, particularly in CMS environments where user-generated content is processed and rendered. Security teams should also consider implementing web application firewalls to detect and block suspicious svg content and event handler patterns that may indicate attempts to exploit this vulnerability, as well as conducting regular security assessments to identify similar input validation weaknesses in other application components that could be exploited through similar attack vectors.