Impact
If using affected versions to determine a URL's hostname, the hostname can be spoofed by using a backslash (\) character as part of the scheme delimiter, e.g. scheme:/\hostname. If the hostname is used in security decisions, the decision may be incorrect.
Depending on library usage and attacker intent, impacts may include allow/block list bypasses, SSRF attacks, open redirects, or other undesired behavior.
Example URL: https:/\expected-example.com/path
Escaped string: https:/\\expected-example.com/path (JavaScript strings must escape backslash)
Affected versions incorrectly return no hostname. Patched versions correctly return expected-example.com. Patched versions match the behavior of other parsers which implement the WHATWG URL specification, including web browsers and Node's built-in URL class.
Patches
Version 1.19.6 is patched against all known payload variants.
References
https://github.com/medialize/URI.js/releases/tag/v1.19.6 (fix for this particular bypass)
https://github.com/medialize/URI.js/releases/tag/v1.19.4 (fix for related bypass)
https://github.com/medialize/URI.js/releases/tag/v1.19.3 (fix for related bypass)
PR #233 (initial fix for backslash handling)
For more information
If you have any questions or comments about this advisory, open an issue in https://github.com/medialize/URI.js
Reporter credit
Yaniv Nizry from the CxSCA AppSec team at Checkmarx
References
Yaniv-git Analyst
Impact
If using affected versions to determine a URL's hostname, the hostname can be spoofed by using a backslash (
\) character as part of the scheme delimiter, e.g.scheme:/\hostname. If the hostname is used in security decisions, the decision may be incorrect.Depending on library usage and attacker intent, impacts may include allow/block list bypasses, SSRF attacks, open redirects, or other undesired behavior.
Example URL:
https:/\expected-example.com/pathEscaped string:
https:/\\expected-example.com/path(JavaScript strings must escape backslash)Affected versions incorrectly return no hostname. Patched versions correctly return
expected-example.com. Patched versions match the behavior of other parsers which implement the WHATWG URL specification, including web browsers and Node's built-in URL class.Patches
Version 1.19.6 is patched against all known payload variants.
References
https://github.com/medialize/URI.js/releases/tag/v1.19.6 (fix for this particular bypass)
https://github.com/medialize/URI.js/releases/tag/v1.19.4 (fix for related bypass)
https://github.com/medialize/URI.js/releases/tag/v1.19.3 (fix for related bypass)
PR #233 (initial fix for backslash handling)
For more information
If you have any questions or comments about this advisory, open an issue in https://github.com/medialize/URI.js
Reporter credit
Yaniv Nizry from the CxSCA AppSec team at Checkmarx
References