CVE-2015-5521 in BlackCat
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in BlackCat CMS 1.1.2 allows remote attackers to inject arbitrary web script or HTML via the name in a new group to backend/groups/index.php.
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Analysis
by VulDB Data Team • 06/01/2022
The CVE-2015-5521 vulnerability represents a critical cross-site scripting flaw within BlackCat CMS version 1.1.2 that exposes the content management system to remote code execution through malicious web script injection. This vulnerability specifically targets the backend groups management interface at backend/groups/index.php where user input is not properly sanitized or validated before being rendered back to users. The flaw occurs when an attacker manipulates the name parameter during group creation, allowing malicious payloads to be stored and subsequently executed in the context of other users' browsers who access the affected page.
This vulnerability falls under the CWE-79 category of Cross-Site Scripting, which is classified as a fundamental web application security weakness that enables attackers to inject client-side scripts into web pages viewed by other users. The specific implementation flaw occurs in the input validation and output encoding processes within the CMS's administrative interface, where user-supplied data flows directly into the HTML output without proper sanitization mechanisms. The attack vector is particularly dangerous because it operates within the backend administrative context, potentially allowing attackers to escalate privileges or execute malicious code with elevated permissions.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable attackers to perform session hijacking, steal administrative credentials, or redirect users to malicious websites. When an attacker successfully injects malicious JavaScript into the group name field, any user who views the affected page becomes susceptible to the payload execution, creating a persistent threat that can compromise multiple user sessions. The vulnerability's exploitation potential is amplified by the fact that it resides in an administrative interface, which typically requires elevated privileges and contains sensitive data, making the compromise of such areas particularly damaging to organizational security posture.
Organizations utilizing BlackCat CMS 1.1.2 should immediately implement multiple layers of defense to mitigate this vulnerability. The primary mitigation strategy involves implementing strict input validation and output encoding for all user-supplied data within the CMS, particularly in administrative interfaces where privilege escalation risks are highest. The implementation should follow the principle of least privilege and include proper HTML escaping of all dynamic content before rendering. Additionally, organizations should consider implementing Content Security Policy headers to limit the execution of unauthorized scripts and establish regular security audits of CMS components. This vulnerability also underscores the importance of keeping CMS platforms updated, as newer versions typically include enhanced security measures and proper input sanitization that prevent such injection attacks from occurring. The ATT&CK framework categorizes this vulnerability under T1059.007 for Scripting and T1566 for Phishing, indicating that exploitation typically involves crafting malicious scripts that can be delivered through web-based attacks. Organizations should also consider network segmentation and monitoring to detect potential exploitation attempts, as the vulnerability can be leveraged to establish persistent access to systems through the administrative interface.