CVE-2023-47641

aiohttp socket poisoning

• CVSS 6.5
• CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
• Input Validation and Sanitization
• Remote

aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. Affected versions of aiohttp have a security vulnerability regarding the inconsistent interpretation of the http protocol. HTTP/1.1 is a persistent protocol, if both Content-Length(CL) and Transfer-Encoding(TE) header values are present it can lead to incorrect interpretation of two entities that parse the HTTP and we can poison other sockets with this incorrect interpretation. A possible Proof-of-Concept (POC) would be a configuration with a reverse proxy(frontend) that accepts both CL and TE headers and aiohttp as backend. As aiohttp parses anything with chunked, we can pass a chunked123 as TE, the frontend entity will ignore this header and will parse Content-Length. The impact of this vulnerability is that it is possible to bypass any proxy rule, poisoning sockets to other users like passing Authentication Headers, also if it is present an Open Redirect an attacker could combine it to redirect random users to another website and log the request. This vulnerability has been addressed in release 3.8.0 of aiohttp. Users are advised to upgrade. There are no known workarounds for this vulnerability.

CVE

CVE-2023-47641

CWE

CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

CVSS base score

6.5

Published

2023-11-14

OWASP

A05 Security Misconfiguration

Orthogonal defect classification

Function

Code defect classification

Incorrect Functionality

Category

Input Validation and Sanitization

Subcategory

Insecure Parsing or Deserialization

Accessibility scope

Remote

Impact

Unauthorized Access

Fixed by upgrading

Yes

Solution

Upgrade to aiohttp version 3.8.0 or later

from aiohttp import web

async def handle(request):
    
    content_length = request.headers.get('Content-Length')
    transfer_encoding = request.headers.get('Transfer-Encoding')

    if transfer_encoding and 'chunked' in transfer_encoding:
        return web.Response(text="Handled with Transfer-Encoding: chunked")
    elif content_length:
        return web.Response(text="Handled with Content-Length")

    return web.Response(text="Hello, world")

app = web.Application()
app.router.add_get('/', handle)

if __name__ == '__main__':
    web.run_app(app, port=8080)

from aiohttp import web

async def handle(request):
    content_length = request.headers.get('Content-Length')
    transfer_encoding = request.headers.get('Transfer-Encoding')

    if content_length and transfer_encoding:
        return web.Response(status=400, text="Bad Request: Conflicting headers")

    if transfer_encoding and 'chunked' in transfer_encoding.lower():
        return web.Response(text="Handled with Transfer-Encoding: chunked")
    elif content_length:
        return web.Response(text="Handled with Content-Length")

    return web.Response(text="Hello, world")

app = web.Application()
app.router.add_get('/', handle)

if __name__ == '__main__':
    web.run_app(app, port=8080)

@misc{vaitp:cve202347641,
  title        = {{aiohttp socket poisoning}},
  author       = {Bogaerts, Fr\'ed\'eric and Ivaki, Naghmeh and Fonseca, Jos\'e},
  year         = {2023},
  note         = {VAITP Python Vulnerability Dataset, entry CVE-2023-47641},
  howpublished = {\url{https://netpack.pt/vaitp/vulnerability/CVE-2023-47641/}}
}