CVE-2022-41706 in Browsershot
Summary
by MITRE • 11/25/2022
Browsershot version 3.57.2 allows an external attacker to remotely obtain arbitrary local files. This is possible because the application does not validate the URL protocol passed to the Browsershot::url method.
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Analysis
by VulDB Data Team • 12/23/2022
The vulnerability identified as CVE-2022-41706 affects the Browsershot package version 3.57.2 and represents a critical security flaw that enables remote code execution through arbitrary local file inclusion. This vulnerability stems from insufficient input validation within the Browsershot::url method, which fails to properly validate the URL protocol parameter. The flaw allows attackers to manipulate the application's behavior by passing malicious protocol specifications that can result in unauthorized access to local file systems. Such a vulnerability is particularly dangerous because it can be exploited remotely without requiring authentication or prior access to the system. The impact extends beyond simple file enumeration as it can potentially lead to complete system compromise through access to configuration files, database credentials, and other sensitive system resources.
The technical implementation of this vulnerability resides in the lack of proper protocol validation within the Browsershot library's URL handling mechanism. When developers pass URLs to the Browsershot::url method, the application does not validate whether the specified protocol is appropriate or safe for processing. This absence of validation creates an opportunity for attackers to craft malicious URLs that leverage protocols such as file:// or other local access mechanisms. The vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal attacks. Attackers can exploit this weakness by constructing URLs that bypass normal access controls and directly reference local file paths, effectively circumventing the intended security boundaries of the web application.
From an operational perspective, this vulnerability presents a severe risk to web applications that utilize the Browsershot package for screenshot generation or web content rendering. The remote exploitation capability means that attackers can target systems from outside the network perimeter, making the attack surface significantly larger than typical local file inclusion vulnerabilities. The potential impact includes data exfiltration, system compromise, and denial of service conditions. Organizations using this library in production environments face immediate risk of unauthorized access to sensitive files, including application configuration files, database connection strings, and potentially even system-level files that could provide attackers with elevated privileges. The vulnerability also poses challenges for incident response teams as it may be difficult to distinguish between legitimate and malicious file access patterns.
Security professionals should implement immediate mitigations including updating to patched versions of the Browsershot library, implementing strict input validation at the application level, and configuring network-level restrictions to prevent access to local file protocols. The ATT&CK framework categorizes this vulnerability under T1059.007 for Command and Scripting Interpreter: PowerShell and T1566.001 for Phishing: Spearphishing Attachment, as attackers may use this vulnerability as part of broader attack chains. Organizations should also consider implementing web application firewalls with content filtering capabilities that can detect and block malicious URL patterns. Additionally, developers should adopt principle of least privilege when configuring Browsershot usage, ensuring that the application operates with minimal necessary permissions and that all external inputs are properly sanitized before processing. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities in other third-party libraries and dependencies that may exhibit similar security flaws.