Vulnerability: Double Slash Bypass in dotCMS NormalizationFilter

CVE-2023-3042 · MEDIUM Severity

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

In dotCMS, versions mentioned, a flaw in the NormalizationFilter does not strip double slashes (//) from URLs, potentially enabling bypasses for XSS and access controls. An example affected URL is https://demo.dotcms.com//html/portlet/ext/files/edit_text_inc.jsp https://demo.dotcms.com//html/portlet/ext/files/edit_text_inc.jsp , which should return a 404 response but didn't. The oversight in the default invalid URL character list can be viewed at the provided GitHub link https://github.com/dotCMS/core/blob/master/dotCMS/src/main/java/com/dotcms/filters/NormalizationFilter.java#L37 .  To mitigate, users can block URLs with double slashes at firewalls or utilize dotCMS config variables. Specifically, they can use the DOT_URI_NORMALIZATION_FORBIDDEN_STRINGS environmental variable to add // to the list of invalid strings. Additionally, the DOT_URI_NORMALIZATION_FORBIDDEN_REGEX variable offers more detailed control, for instance, to block //html.* URLs. Fix Version:23.06+, LTS 22.03.7+, LTS 23.01.4+

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