CVE-2017-16214 in peiserver
Summary
by MITRE
peiserver is a static file server. peiserver is vulnerable to a directory traversal issue, giving an attacker access to the filesystem by placing "../" in the url.
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Analysis
by VulDB Data Team • 02/16/2020
The CVE-2017-16214 vulnerability affects peiserver, a static file server implementation that suffers from a critical directory traversal flaw. This vulnerability arises from inadequate input validation and path sanitization within the server's request handling mechanism, allowing malicious actors to access arbitrary files on the underlying filesystem through carefully crafted URL parameters. The flaw specifically manifests when the server fails to properly sanitize user-supplied paths that contain directory traversal sequences such as "../" which are commonly used to navigate up directory levels in file systems. This type of vulnerability represents a classic example of improper input validation and path handling that has been consistently identified in security frameworks and standards.
The technical exploitation of this vulnerability occurs when an attacker submits a URL containing directory traversal sequences to the peiserver application. The server processes these sequences without adequate sanitization, allowing the attacker to traverse the file system hierarchy and access files that should remain protected within the server's document root. This can potentially lead to unauthorized access to sensitive configuration files, source code, user data, or system files that contain credentials, authentication tokens, or other confidential information. The vulnerability operates at the application layer and can be exploited through HTTP requests without requiring authentication, making it particularly dangerous in environments where the server is accessible to unauthenticated users. This flaw aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks.
The operational impact of CVE-2017-16214 extends beyond simple unauthorized file access, as it can provide attackers with significant footholds for further exploitation within affected systems. An attacker who successfully exploits this vulnerability can potentially access not only static files but also sensitive system information that may reveal the server's configuration, installed software versions, or even system architecture details. This reconnaissance information can be leveraged to identify additional vulnerabilities or attack vectors within the broader system. The vulnerability also poses risks to data confidentiality and integrity, as attackers can potentially read, modify, or delete files within the server's accessible directories. From an attacker's perspective, this vulnerability aligns with several techniques documented in the MITRE ATT&CK framework, particularly those related to credential access and defense evasion, as the ability to traverse directories and access sensitive files can lead to privilege escalation or data exfiltration.
Mitigation strategies for CVE-2017-16214 should focus on implementing robust input validation and path sanitization mechanisms within the peiserver application. Organizations should ensure that all user-supplied paths are properly validated and sanitized to prevent directory traversal sequences from being processed. The implementation of a whitelist-based approach for acceptable file paths, combined with proper directory structure enforcement, can effectively prevent unauthorized access attempts. Additionally, the server should be configured to operate within a restricted directory context, limiting the scope of accessible files even if traversal attempts are partially successful. Regular security updates and patches should be applied to ensure that known vulnerabilities are addressed promptly. Network-level controls such as web application firewalls can provide additional layers of protection by detecting and blocking suspicious URL patterns that may indicate directory traversal attempts. The vulnerability also underscores the importance of following secure coding practices and conducting regular security assessments to identify and remediate similar weaknesses in application code.