CVE-2023-27419 in Viable Blog Plugin
Summary
by MITRE • 05/10/2023
Unauth. Reflected Cross-Site Scripting (XSS) vulnerability in Everest themes Viable Blog theme
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Analysis
by VulDB Data Team • 05/21/2023
The vulnerability CVE-2023-27419 represents an unauthorized reflected cross-site scripting flaw discovered in the Viable Blog theme for Everest themes. This security weakness allows attackers to inject malicious scripts into web pages viewed by other users, potentially compromising user sessions and data integrity. The issue specifically affects the Viable Blog theme implementation where user input parameters are not properly sanitized before being reflected back to the browser. Such vulnerabilities fall under the CWE-79 category which defines cross-site scripting as a common web application security flaw occurring when untrusted data is directly included in dynamic web content without proper validation or encoding. The attack vector typically involves sending malicious links to victims through social engineering or phishing techniques, where the crafted payload gets executed in the victim's browser context.
The technical implementation of this reflected XSS vulnerability stems from improper input validation within the theme's PHP code handling user-supplied parameters. When users interact with the blog theme through various interface elements such as search functions, contact forms, or navigation parameters, the theme fails to adequately sanitize or encode these inputs before incorporating them into HTML responses. This allows attackers to craft malicious payloads that execute in the context of the victim's browser session. The vulnerability is classified as a reflected XSS because the malicious script is reflected off the web server, typically through a URL parameter, and executed immediately when the victim clicks on the malicious link. This type of vulnerability is particularly dangerous because it requires no persistent storage of malicious code on the server, making detection more challenging for administrators.
The operational impact of this vulnerability extends beyond simple script execution, potentially enabling session hijacking, credential theft, and data manipulation within the targeted web application. Attackers could exploit this weakness to steal user authentication tokens, redirect victims to malicious sites, or inject additional malicious content that could persist through other vulnerable components. The vulnerability affects any user who interacts with the compromised theme, making it particularly concerning for high-traffic blogs or websites where user engagement is frequent. From an ATT&CK framework perspective, this vulnerability maps to T1566.001 (Phishing) and T1584.002 (Compromise Software Supply Chain) as attackers could leverage this weakness to establish persistent access or create more sophisticated attack chains. The reflected nature of the vulnerability means that attackers need to actively deliver malicious payloads through external channels rather than exploiting server-side weaknesses.
Mitigation strategies for CVE-2023-27419 should focus on immediate input validation and output encoding practices within the theme's codebase. The primary remediation involves implementing proper sanitization of all user-supplied inputs through functions like htmlspecialchars() or similar encoding mechanisms before rendering any user data in HTML contexts. Security patches should be applied immediately from the theme developers, and administrators should consider implementing Content Security Policy headers to provide additional defense-in-depth measures. Regular security audits of theme code should be conducted to identify similar vulnerabilities, particularly focusing on parameter handling and input validation routines. The vulnerability also highlights the importance of keeping all theme and plugin components updated, as outdated software often contains known security flaws that attackers actively exploit. Organizations should also implement web application firewalls to detect and block malicious traffic patterns associated with XSS attempts, providing an additional layer of protection against such reflected attacks.