CVE-2017-16038 in f2e-server
Summary
by MITRE
`f2e-server` 1.12.11 and earlier is vulnerable to a directory traversal issue, giving an attacker access to the filesystem by placing "../" in the url. This is compounded by `f2e-server` requiring elevated privileges to run.
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Analysis
by VulDB Data Team • 03/21/2023
The vulnerability identified as CVE-2017-16038 affects f2e-server versions 1.12.11 and earlier, presenting a critical directory traversal flaw that enables unauthorized file system access through manipulated URL parameters. This weakness arises from insufficient input validation within the server's path handling mechanism, allowing attackers to navigate beyond the intended directory structure by injecting ../ sequences into web requests. The vulnerability's severity is amplified by the fact that f2e-server typically operates with elevated privileges, meaning that successful exploitation could grant attackers root-level access to the underlying operating system and all associated resources. The directory traversal issue stems from the server's failure to properly sanitize user-supplied input before processing file paths, creating a pathway for malicious actors to access sensitive files, configuration data, and system resources that should remain protected. This flaw directly maps to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal vulnerabilities. The operational impact extends beyond simple file access, as attackers could potentially read system configuration files, access database credentials, examine application source code, or even execute arbitrary commands if the server's privileges permit such actions. The vulnerability's exploitation is straightforward and requires minimal technical skill, making it particularly dangerous in environments where f2e-server is deployed without proper network segmentation or additional security controls. When combined with the server's requirement for elevated privileges, this creates a scenario where a single successful attack could compromise the entire system. The attack vector demonstrates characteristics aligned with ATT&CK technique T1083, which covers File and Directory Discovery, as attackers can systematically explore the file system structure to identify valuable targets. Organizations running vulnerable versions of f2e-server face significant risk of data breaches, system compromise, and potential lateral movement within their networks. The vulnerability's persistence is concerning as it affects the core functionality of the server's file handling capabilities, making it difficult to remediate without either patching the software or implementing compensating controls. Given that this vulnerability was present in versions up to 1.12.11, it represents a long-standing issue that organizations may have been unknowingly exposed to for extended periods, particularly in environments where automated patch management processes were insufficient or absent. The exploitation of this vulnerability requires no specialized tools beyond standard web browsing capabilities, making it accessible to threat actors of varying skill levels. Security professionals should note that this issue underscores the importance of implementing proper input validation, least privilege principles, and regular security assessments to identify and remediate similar vulnerabilities across all system components. The combination of directory traversal capability with elevated privilege execution creates a particularly dangerous scenario that aligns with ATT&CK technique T1566, which covers Phishing for Information, as attackers may use this vulnerability to harvest sensitive data from compromised systems. Organizations must ensure that all instances of f2e-server are updated to versions that properly address this directory traversal vulnerability, while also implementing network segmentation to limit potential damage from successful exploitation attempts. The vulnerability serves as a reminder of the critical importance of validating all user inputs and implementing robust access controls, particularly for services that operate with elevated system privileges and handle file system operations.