CVE-2019-18653 in Avast
Summary
by MITRE
A Cross Site Scripting (XSS) issue exists in Avast AntiVirus (Free, Internet Security, and Premiere Edition) 19.3.2369 build 19.3.4241.440 in the Network Notification Popup, allowing an attacker to execute JavaScript code via an SSID Name.
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Analysis
by VulDB Data Team • 02/01/2024
The vulnerability CVE-2019-18653 represents a critical cross site scripting flaw in Avast AntiVirus software across multiple editions including Free, Internet Security, and Premiere versions. This security weakness specifically manifests within the Network Notification Popup component of the software, creating an attack vector where malicious actors can inject and execute arbitrary JavaScript code through manipulation of SSID names. The vulnerability affects version 19.3.2369 build 19.3.4241.440, indicating a specific software release where proper input validation mechanisms failed to adequately sanitize user-supplied network identifiers.
The technical exploitation of this vulnerability occurs when the Avast antivirus software displays network notifications to users, particularly when encountering wireless network identifiers that contain maliciously crafted script payloads. The flaw stems from insufficient sanitization of SSID names before rendering them in the popup interface, allowing attackers to inject script tags or other malicious code that executes within the context of the user's browser or application environment. This type of vulnerability falls under CWE-79 which specifically addresses Cross-Site Scripting and aligns with ATT&CK technique T1566.001 for initial access through spearphishing attachments, though in this case the attack vector is more subtle and occurs through network notification mechanisms.
The operational impact of this vulnerability extends beyond simple script execution as it provides attackers with potential access to sensitive user information and system resources. When users encounter network notifications displaying malicious SSID names, the injected JavaScript code can perform actions such as stealing session cookies, redirecting users to malicious websites, or even executing additional payloads that could compromise the entire system. The vulnerability is particularly concerning because it leverages the trusted context of network notifications, making users more likely to interact with the malicious content without suspicion. Attackers can exploit this by creating wireless networks with maliciously crafted SSID names that contain embedded scripts, potentially leading to full system compromise when users view these notifications.
Mitigation strategies for CVE-2019-18653 require immediate software updates from Avast to address the input validation deficiencies in the Network Notification Popup component. Organizations should implement network monitoring solutions to detect and prevent creation of malicious SSID names, while users must be educated about the risks of connecting to unknown wireless networks. Network administrators should consider implementing wireless network segmentation and access controls to limit potential attack surfaces. Additionally, browser security settings can be adjusted to restrict script execution in notification contexts, though the most effective solution remains the official software patch provided by Avast. The vulnerability demonstrates the importance of input sanitization in security software, as even protective tools can become attack vectors when proper validation mechanisms are absent. This issue also highlights the need for comprehensive security testing of notification and user interface components, as these areas are often overlooked in traditional vulnerability assessments but represent significant attack surfaces for social engineering and code execution attacks.