CVE-2017-9441 in BigTree
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in BigTree CMS through 4.2.18 allow remote authenticated users to inject arbitrary web script or HTML by uploading a crafted package, triggering mishandling of the (1) title or (2) version or (3) author_name parameter in manifest.json. This issue exists in core\admin\modules\developer\extensions\install\unpack.php and core\admin\modules\developer\packages\install\unpack.php. NOTE: the vendor states "You must implicitly trust any package or extension you install as they all have the ability to write PHP files.
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Analysis
by VulDB Data Team • 08/16/2024
The CVE-2017-9441 vulnerability represents a critical cross-site scripting flaw in BigTree CMS versions up to 4.2.18 that demonstrates a fundamental weakness in the content management system's package installation and handling mechanisms. This vulnerability specifically targets the manifest.json file processing within the developer module's extension and package installation components, creating a pathway for authenticated attackers to inject malicious scripts into the system. The flaw occurs in two primary locations: core/admin/modules/developer/extensions/install/unpack.php and core/admin/modules/developer/packages/install/unpack.php, where the system fails to properly sanitize user-supplied data during package installation processes. The vulnerability is particularly concerning because it requires only authenticated access, meaning that users with legitimate administrative privileges could exploit this flaw to compromise the entire system. The attack vector involves uploading a malicious package that contains crafted values for the title, version, or author_name parameters within the manifest.json file, which are then improperly rendered in the web interface without adequate input validation or output encoding.
The technical exploitation of this vulnerability follows a well-established XSS pattern that aligns with CWE-79, which specifically addresses cross-site scripting flaws in web applications. The flaw stems from the improper handling of user-controllable input within the package installation workflow, where the system directly incorporates manifest.json parameters into HTML output without appropriate sanitization or encoding measures. This creates a persistent XSS condition that can affect any user who views the malicious package information within the BigTree CMS admin interface. The vulnerability's impact is amplified by the fact that it operates within the core administrative modules, providing attackers with access to sensitive system information and potentially enabling further exploitation. The issue is classified as a server-side XSS vulnerability because the malicious code executes within the context of the victim's browser when they interact with the vulnerable package information, rather than being stored on the server itself. The attacker can leverage this vulnerability to steal session cookies, redirect users to malicious sites, or perform actions on behalf of authenticated users with the privileges of the compromised account.
The operational impact of CVE-2017-9441 extends beyond simple script injection, as it fundamentally undermines the security model of the BigTree CMS platform. Since the system requires implicit trust for all installed packages, attackers can potentially escalate privileges or gain unauthorized access to sensitive data through the injected malicious code. The vulnerability affects the entire package management ecosystem, including both extensions and packages, making it a systemic security weakness rather than an isolated flaw. This issue particularly impacts organizations that rely heavily on third-party extensions or packages, as the vulnerability can be exploited through seemingly legitimate installation processes. The attack scenario becomes more dangerous when considering that administrators might unknowingly install malicious packages that have been tampered with, creating a persistent backdoor or data exfiltration mechanism. The vulnerability's presence in core administrative modules means that successful exploitation could lead to complete system compromise, especially when combined with other potential attack vectors within the CMS. The flaw also creates potential for privilege escalation attacks, where attackers could leverage the XSS to gain higher-level administrative access or manipulate system configurations.
Mitigation strategies for CVE-2017-9441 should focus on both immediate remediation and long-term architectural improvements. The most effective immediate solution involves upgrading to BigTree CMS version 4.2.19 or later, where the vulnerability has been patched through proper input validation and output encoding mechanisms. Organizations should implement strict package validation procedures that include manual review of manifest.json files and automated scanning for suspicious content before package installation. The vendor's statement regarding implicit trust highlights the importance of implementing additional security layers beyond the default system behavior, including network segmentation and monitoring of package installation activities. Security teams should establish comprehensive logging and monitoring of administrative package installation events to detect potential exploitation attempts. The implementation of Content Security Policy headers can provide an additional defensive layer against XSS attacks, although this is a secondary measure that does not address the root cause. Organizations should also consider implementing automated security scanning tools that can identify potentially malicious package content during the upload process. The vulnerability serves as a reminder of the critical importance of proper input validation and output encoding practices, particularly within administrative interfaces where the attack surface is most significant. Regular security assessments of package management systems and user access controls are essential to prevent exploitation of similar vulnerabilities in the future.