CVE-2017-16103 in serveryztyzt
Summary
by MITRE
serveryztyzt is a simple http server. serveryztyzt 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 • 02/15/2020
The vulnerability identified as CVE-2017-16103 affects serveryztyzt, a lightweight http server implementation that suffers from a critical directory traversal flaw. This issue stems from inadequate input validation within the server's URL parsing mechanism, allowing malicious actors to access arbitrary files on the underlying filesystem through crafted requests containing directory traversal sequences. The vulnerability represents a classic path traversal attack vector that exploits the server's failure to properly sanitize user-supplied URL parameters before processing file requests.
This directory traversal vulnerability operates by permitting attackers to manipulate the URL path through the use of "../" sequences that navigate up the directory structure. When the server processes these malformed paths without proper validation, it can access files outside of its intended serving directory, potentially exposing sensitive system information, configuration files, or even system binaries. The flaw essentially allows an attacker to bypass the server's intended file access restrictions and gain unauthorized access to the underlying filesystem, which constitutes a severe security compromise.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can enable attackers to execute arbitrary code on the affected system or cause denial of service conditions. An attacker could potentially access system credentials, application configuration files, user data, or even escalate privileges by accessing system binaries. The vulnerability's exploitation requires minimal technical knowledge, making it particularly dangerous as it can be leveraged by attackers with varying skill levels. According to the CWE catalog, this maps to CWE-22: Improper Limiting of a Pathname to a Restricted Directory ('Path Traversal') which is classified as a high-severity issue due to its potential for significant system compromise.
Mitigation strategies for this vulnerability should focus on implementing robust input validation and sanitization mechanisms within the server's request processing pipeline. The recommended approach involves normalizing all incoming URLs to ensure that directory traversal sequences are properly detected and rejected before any file operations are performed. Additionally, the server should operate with minimal required privileges and implement proper access controls to limit the damage that could occur even if the vulnerability is exploited. Organizations should also consider implementing web application firewalls or security monitoring systems that can detect and block suspicious URL patterns. The ATT&CK framework categorizes this type of vulnerability under T1059.007: Command and Scripting Interpreter: PowerShell, as exploitation often involves command execution through the compromised server. Regular security audits and input validation testing should be performed to identify similar vulnerabilities in other applications and services that may be susceptible to the same class of attacks.