CVE-2021-41125

Scrapy exposes HTTP authentication credentials in requests

• CVSS 6.5
• CWE-522
• Authentication, Authorization, and Session Management
• Remote

Scrapy is a high-level web crawling and scraping framework for Python. If you use `HttpAuthMiddleware` (i.e. the `http_user` and `http_pass` spider attributes) for HTTP authentication, all requests will expose your credentials to the request target. This includes requests generated by Scrapy components, such as `robots.txt` requests sent by Scrapy when the `ROBOTSTXT_OBEY` setting is set to `True`, or as requests reached through redirects. Upgrade to Scrapy 2.5.1 and use the new `http_auth_domain` spider attribute to control which domains are allowed to receive the configured HTTP authentication credentials. If you are using Scrapy 1.8 or a lower version, and upgrading to Scrapy 2.5.1 is not an option, you may upgrade to Scrapy 1.8.1 instead. If you cannot upgrade, set your HTTP authentication credentials on a per-request basis, using for example the `w3lib.http.basic_auth_header` function to convert your credentials into a value that you can assign to the `Authorization` header of your request, instead of defining your credentials globally using `HttpAuthMiddleware`.

CVE

CVE-2021-41125

CWE

CWE-522

CVSS base score

6.5

Published

2021-10-06

OWASP

A05 Security Misconfiguration

Orthogonal defect classification

Function

Code defect classification

Incorrect Functionality

Category

Authentication, Authorization, and Session Management

Subcategory

Insecure Authentication Mechanisms

Accessibility scope

Remote

Impact

Information Disclosure

Fixed by upgrading

Yes

Solution

Upgrade to Scrapy 2.5.1 and use http_auth_domain attribute to control credentials exposure.

import scrapy

class MySpider(scrapy.Spider):
    name = 'my_spider'
    http_user = 'your_username'
    http_pass = 'your_password'

    def start_requests(self):
        urls = [
            'http://example.com',
            'http://anotherdomain.com'
        ]
        for url in urls:
            yield scrapy.Request(url)

import scrapy
from w3lib.http import basic_auth_header

class MySpider(scrapy.Spider):
    name = 'my_spider'
    http_user = 'your_username'
    http_pass = 'your_password'
    http_auth_domain = ['example.com']

    def start_requests(self):
        urls = [
            'http://example.com',
            'http://anotherdomain.com'
        ]
        for url in urls:
            if self.is_auth_domain(url):
                yield scrapy.Request(url, headers={'Authorization': basic_auth_header(self.http_user, self.http_pass)})
            else:
                yield scrapy.Request(url)

    def is_auth_domain(self, url):
        return any(domain in url for domain in self.http_auth_domain)

@misc{vaitp:cve202141125,
  title        = {{Scrapy exposes HTTP authentication credentials in requests}},
  author       = {Bogaerts, Fr\'ed\'eric and Ivaki, Naghmeh and Fonseca, Jos\'e},
  year         = {2021},
  note         = {VAITP Python Vulnerability Dataset, entry CVE-2021-41125},
  howpublished = {\url{https://netpack.pt/vaitp/vulnerability/CVE-2021-41125/}}
}