CVE-2020-25877 in BlackCat
Summary
by MITRE • 07/10/2021
A stored cross site scripting (XSS) vulnerability in the 'Add Page' feature of BlackCat CMS 1.3.6 allows authenticated attackers to execute arbitrary web scripts or HTML via a crafted payload entered into the 'Title' parameter.
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Analysis
by VulDB Data Team • 07/15/2021
The vulnerability CVE-2020-25877 represents a critical stored cross site scripting flaw within BlackCat CMS version 1.3.6 that specifically targets the 'Add Page' functionality. This issue arises from inadequate input validation and sanitization mechanisms within the content management system's administrative interface, where user-supplied data is not properly escaped or filtered before being stored in the database and subsequently rendered back to users. The vulnerability affects authenticated users who possess sufficient privileges to create or modify pages within the CMS, making it particularly concerning as it can be exploited by insiders or compromised accounts with administrative access. The attack vector specifically targets the 'Title' parameter, which serves as the primary entry point for malicious payload injection, allowing attackers to bypass standard security controls that typically protect against such attacks.
The technical exploitation of this vulnerability follows a well-established XSS attack pattern where malicious scripts are stored on the server and executed whenever legitimate users view the affected content. When an attacker submits a crafted payload through the 'Title' field during page creation, the CMS fails to properly sanitize the input, allowing HTML tags and JavaScript code to be persisted in the database. Subsequently, when other users navigate to pages containing this malicious title, their browsers execute the embedded scripts within the context of the vulnerable CMS application. This stored nature of the vulnerability means that the malicious code remains active until manually removed from the database, potentially affecting multiple users over extended periods. The vulnerability aligns with CWE-79 which defines cross site scripting as the failure to properly escape output, and specifically relates to CWE-80 which addresses the improper neutralization of script-related HTML tags in a web page.
The operational impact of CVE-2020-25877 extends beyond simple script execution, as it can enable sophisticated attack chains that compromise user sessions, steal sensitive data, or redirect users to malicious sites. Attackers can leverage this vulnerability to perform session hijacking by stealing cookies, inject malicious redirects that lead to phishing pages, or deploy additional malware through browser-based attack vectors. The authenticated nature of the vulnerability means that attackers can potentially access sensitive administrative functions, modify content, or even escalate privileges within the CMS environment. This makes the vulnerability particularly dangerous in environments where CMS administrators have elevated access rights or where the CMS is used to manage sensitive organizational content. The attack can be particularly insidious as it operates within the legitimate application context, making detection more difficult for network security tools and users who may not immediately recognize the malicious activity.
Organizations affected by this vulnerability should implement immediate mitigations including input validation and sanitization of all user-supplied data, particularly in administrative interfaces where content is stored and later rendered. The recommended approach involves implementing proper HTML escaping mechanisms that convert special characters into their safe representations before storing data, as well as implementing Content Security Policy headers to limit script execution capabilities. Additionally, regular security audits and penetration testing should be conducted to identify similar vulnerabilities in other CMS components or custom applications. The remediation process should include updating to BlackCat CMS version 1.3.7 or later where this vulnerability has been addressed through proper input sanitization and validation controls. Security teams should also consider implementing web application firewalls and monitoring for suspicious input patterns that may indicate attempted exploitation of similar vulnerabilities. According to ATT&CK framework, this vulnerability maps to T1059.001 for command and scripting interpreter and T1566.001 for credential access through social engineering, highlighting the potential for broader attack surface exploitation beyond simple XSS execution.