CVE-2023-48003 in Asp.Net Zero
Summary
by MITRE • 12/27/2023
An open redirect through HTML injection in user messages in Asp.Net Zero before 12.3.0 allows remote attackers to redirect targeted victims to any URL via the '<meta http-equiv="refresh"' in the WebSocket messages.
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Analysis
by VulDB Data Team • 01/19/2024
This vulnerability exists in the Asp.Net Zero framework prior to version 12.3.0 and represents a critical security flaw that enables remote attackers to perform open redirect attacks through HTML injection in user messages. The vulnerability specifically manifests through WebSocket messages where malicious actors can inject HTML content containing meta refresh tags that redirect users to arbitrary URLs. This issue falls under the CWE-601 open redirect vulnerability category, which is classified as a serious weakness in web applications that can be exploited to deceive users into visiting malicious sites. The attack vector leverages the WebSocket communication channel within the Asp.Net Zero platform, where user-generated content is not properly sanitized before being transmitted to other users.
The technical implementation of this vulnerability occurs when user messages containing HTML content are processed and displayed within the WebSocket communication framework. When the system fails to properly sanitize or escape HTML characters in user input, attackers can inject malicious meta refresh tags that automatically redirect users to phishing sites, malware distribution points, or other malicious destinations. The specific injection point involves the '<meta http-equiv="refresh"' HTML element which when properly crafted can cause browsers to automatically redirect users to attacker-controlled URLs without user consent or awareness. This type of attack directly aligns with the ATT&CK technique T1566.001 which covers social engineering through spearphishing attachments and links, making it particularly dangerous in enterprise environments where users may trust internal communications.
The operational impact of this vulnerability extends beyond simple redirection attacks as it can be leveraged for sophisticated phishing campaigns, credential harvesting, and malware delivery operations. Attackers can craft messages that appear legitimate within the Asp.Net Zero application interface while simultaneously redirecting users to malicious external sites. This creates a dangerous scenario where users may unknowingly provide credentials or download malware while believing they are interacting with trusted internal applications. The vulnerability affects the application's integrity and trust model, potentially compromising entire user sessions and enabling further attacks such as session hijacking or privilege escalation. Organizations using affected versions of Asp.Net Zero face significant risk of user compromise and data exfiltration through this open redirect mechanism.
Mitigation strategies for this vulnerability should focus on implementing comprehensive input validation and output encoding throughout the WebSocket message processing pipeline. The primary fix involves ensuring all user-generated content is properly sanitized before being stored or transmitted, with special attention to HTML character encoding and meta tag validation. Organizations should implement strict content security policies that prevent the execution of unauthorized HTML elements within user messages, particularly meta refresh tags and other redirect mechanisms. The recommended solution includes upgrading to Asp.Net Zero version 12.3.0 or later, which contains proper input sanitization and output encoding mechanisms. Additionally, network-level protections such as web application firewalls and URL filtering systems can provide additional layers of defense against exploitation attempts. Security teams should also implement monitoring for suspicious WebSocket message patterns and conduct regular security assessments to identify potential injection points within the application's communication frameworks.