CVE-2024-23334

Directory traversal vulnerability in aiohttp when follow_symlinks is True.

• CVSS 7.5
• CWE-22
• Input Validation and Sanitization
• Remote

aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. When using aiohttp as a web server and configuring static routes, it is necessary to specify the root path for static files. Additionally, the option 'follow_symlinks' can be used to determine whether to follow symbolic links outside the static root directory. When 'follow_symlinks' is set to True, there is no validation to check if reading a file is within the root directory. This can lead to directory traversal vulnerabilities, resulting in unauthorized access to arbitrary files on the system, even when symlinks are not present. Disabling follow_symlinks and using a reverse proxy are encouraged mitigations. Version 3.9.2 fixes this issue.

CVE

CVE-2024-23334

CWE

CWE-22

CVSS base score

7.5

Published

2024-01-29

OWASP

A05 Security Misconfiguration

Orthogonal defect classification

Checking

Code defect classification

Incorrect Check

Category

Input Validation and Sanitization

Subcategory

Path Traversal

Accessibility scope

Remote

Impact

Unauthorized Access

Affected component

aiohttp

Fixed by upgrading

Yes

Solution

Upgrade to aiohttp version 3.9.2 or later and disable follow_symlinks.

from aiohttp import web

async def handle(request):
    return web.FileResponse('./static' + request.match_info['filename'])

app = web.Application()
app.router.add_get('/static/{filename:.*}', handle)

web.run_app(app)

from aiohttp import web
from pathlib import Path

STATIC_DIR = Path('./static').resolve()

async def handle(request):
    filename = request.match_info['filename']
    requested_path = (STATIC_DIR / filename).resolve()

    if not str(requested_path).startswith(str(STATIC_DIR)) or not requested_path.is_file():
        return web.Response(status=403, text="Access denied")

    return web.FileResponse(requested_path)

app = web.Application()
app.router.add_get('/static/{filename:.*}', handle)

web.run_app(app)

GET /static/../../../../etc/passwd HTTP/1.1
Host: vulnerable-server.com

@misc{vaitp:cve202423334,
  title        = {{Directory traversal vulnerability in aiohttp when follow_symlinks is True.}},
  author       = {Bogaerts, Fr\'ed\'eric and Ivaki, Naghmeh and Fonseca, Jos\'e},
  year         = {2024},
  note         = {VAITP Python Vulnerability Dataset, entry CVE-2024-23334},
  howpublished = {\url{https://netpack.pt/vaitp/vulnerability/CVE-2024-23334/}}
}