CVE-2017-16038: Directory Traversal in f2e-server
Platform
nodejs
Component
f2e-server
Fixed in
1.12.12
CVE-2017-16038 is a directory traversal vulnerability affecting versions of the f2e-server software prior to 1.12.12. This flaw allows attackers to navigate outside the intended directory root, potentially exposing sensitive files and data stored on the system. The vulnerability stems from the server's improper handling of relative file paths. An update to version 1.12.12 or later resolves this issue.
Impact and Attack Scenarios
Successful exploitation of CVE-2017-16038 allows an attacker to read arbitrary files from the server's file system. This includes potentially sensitive configuration files, source code, or even user data. The impact can range from information disclosure to complete system compromise, depending on the files accessible and the privileges of the user running the f2e-server process. The provided example request demonstrates how an attacker could use the ../ sequence to traverse up the directory structure and access files like /etc/passwd. While direct system takeover is unlikely without further vulnerabilities, the exposure of sensitive data poses a significant risk.
Exploitation Context
CVE-2017-16038 was published on July 24, 2018. There is no indication of this vulnerability being actively exploited in the wild, nor is it currently listed on KEV or EPSS. Public proof-of-concept (POC) code is readily available, demonstrating the ease of exploitation. The CVSS score of 7.5 (HIGH) reflects the potential for significant impact, although the lack of active exploitation suggests a lower immediate threat.
Threat Intelligence
Exploit Status
EPSS
0.86% (75% percentile)
CVSS Vector
What do these metrics mean?
- Attack Vector
- Network — remotely exploitable over the internet. No physical or local access required. Widest attack surface.
- Attack Complexity
- Low — no special conditions required. Attacker can exploit reliably without depending on rare configurations or timing.
- Privileges Required
- None — unauthenticated. No login or credentials needed to exploit.
- User Interaction
- None — attack is automatic and silent. Victim does nothing: no click, no file open.
- Scope
- Unchanged — impact is limited to the vulnerable component itself.
- Confidentiality
- High — complete confidentiality loss. Attacker can read all data: credentials, keys, personal data.
- Integrity
- None — no integrity impact. Attacker cannot modify data.
- Availability
- None — no availability impact. Service remains fully operational.
Timeline
- Published
- Modified
- EPSS updated
Mitigation and Workarounds
The primary mitigation for CVE-2017-16038 is to upgrade f2e-server to version 1.12.12 or later. If an immediate upgrade is not possible due to compatibility issues or system downtime constraints, consider implementing a Web Application Firewall (WAF) rule to block requests containing directory traversal sequences (e.g., ../). Additionally, restrict file access permissions for the f2e-server user to only the necessary directories. Review and harden the server's configuration to minimize the potential impact of a successful attack. After upgrading, confirm the fix by attempting a directory traversal request (e.g., GET /../../../../../../../../../../etc/passwd HTTP/1.1) and verifying that it is blocked or returns an error.
How to fix
No official patch available. Check for workarounds or monitor for updates.
Frequently asked questions
What is CVE-2017-16038 — Directory Traversal in f2e-server?
CVE-2017-16038 is a vulnerability in f2e-server allowing attackers to access files outside the intended directory, potentially exposing sensitive data.
Am I affected by CVE-2017-16038 in f2e-server?
You are affected if you are running f2e-server versions prior to 1.12.12. Check your version and upgrade immediately.
How do I fix CVE-2017-16038 in f2e-server?
Upgrade to version 1.12.12 or later. As a temporary workaround, implement WAF rules to block directory traversal attempts.
Is CVE-2017-16038 being actively exploited?
There is no current evidence of active exploitation, but public POCs exist, making it a potential risk.
Where can I find the official f2e-server advisory for CVE-2017-16038?
Refer to the vendor's security advisory or relevant security databases for the official advisory regarding CVE-2017-16038.
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