GitHub Advisoryadvisory · RubyGems
GHSA-w3j4-76qw-wwjm Older releases of better_errors open to Cross-Site Request Forgery attack
MEDIUM
Official page ↗
- Aliases
- CVE-2021-39197
- Ecosystem
- RubyGems
- Packages
- better_errors
- Severity
- Moderate
- CVSS vector
- CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N
- Weaknesses
- CWE-352
- Reviewed
- 2021-09-07
Affected packages
• RubyGems better_errors: < 2.8.0 → fixed in 2.8.0
Description
Impact
better_errors prior to 2.8.0 did not implement CSRF protection for its internal requests. It also did not enforce the correct "Content-Type" header for these requests, which allowed a cross-origin "simple request" to be made without CORS protection. These together left an application with better_errors enabled open to cross-origin attacks.
_As a developer tool, better_errors documentation strongly recommends addition only to the `development` bundle group, so this vulnerability should only affect development environments. Please ensure that your project limits better_errors to the `development` group (or the non-Rails equivalent)._
Patches
Starting with release 2.8.x, CSRF protection is enforced. It is recommended that you upgrade to the latest release, or minimally to "~> 2.8.3".
Workarounds
There are no known workarounds to mitigate the risk of using older releases of better_errors.
References
• Chris Moberly provided an example attack that uses a now-patched vulnerability of webpack-dev-server in conjunction with Better Errors
For more information
If you have any questions or comments about this advisory, please
• Add to the discussion in better_errors
• Open an issue in better_errors
Related
Alias · CVE (1)
- CVE-2021-39197 better_errors is an open source replacement for the standard Rails error page with more information rich error pages. vulnerability
Weakness · CWE (1)
- CWE-352 Cross-Site Request Forgery weakness
References
- https://github.com/BetterErrors/better_errors/security/advisories/GHSA-w3j4-76qw-wwjm web
- https://nvd.nist.gov/vuln/detail/CVE-2021-39197 advisory
- https://github.com/BetterErrors/better_errors/pull/474 web
- https://github.com/BetterErrors/better_errors/commit/8e8e796bfbde4aa088741823c8a3fc6df2089bb0 web
- https://github.com/BetterErrors/better_errors package
- https://github.com/BetterErrors/better_errors/discussions/507 web
- https://github.com/rubysec/ruby-advisory-db/blob/master/gems/better_errors/CVE-2021-39197.yml web