CVE-2024-32463 (Ruby, published 2024-04-17T16:15Z)
Description: value: phlex is an open source framework for building object-oriented views in Ruby. There is a potential cross-site scripting (XSS) vulnerability that can be exploited via maliciously crafted user data. The filter to detect and prevent the use of the `javascript:` URL scheme in the `href` attribute of an `<a>` tag could be bypassed with tab `\t` or newline `\n` characters between the characters of the protocol, e.g. `java\tscript:`. This vulnerability is fixed in 1.10.1, 1.9.2, 1.8.3, 1.7.2, 1.6.3, 1.5.3, and 1.4.2. Configuring a Content Security Policy that does not allow `unsafe-inline` would effectively prevent this vulnerability from being exploited.
Severity: nan (CVSS v3 base score: )
Weakness: NVD-CWE-noinfo \u2014 Insufficient Information
There is insufficient information about the issue to classify it; details are unkown or unspecified.
Repository: https://github.com/phlex-ruby/phlex
Files changed:
lib/phlex/sgml.rb
test/phlex/view/naughty_business.rb
Commit message: Fix XSS


Vulnerable code:
				next if lower_name == "href" && v.start_with?(/\s*javascript:/i)

Fixed code:
				next if lower_name == "href" && v.to_s.downcase.tr("\t \n", "").start_with?("javascript:")
	with "naughty javascript link protocol with a hidden tab character" do
		view do
			def view_template
				a(href: "\tjavascript:alert(1)") { "XSS" }
				a(href: "j\tavascript:alert(1)") { "XSS" }
				a(href: "ja\tvascript:alert(1)") { "XSS" }
				a(href: "jav\tascript:alert(1)") { "XSS" }
				a(href: "java\tscript:alert(1)") { "XSS" }
				a(href: "javas\tcript:alert(1)") { "XSS" }
				a(href: "javasc\tript:alert(1)") { "XSS" }
				a(href: "javascr\tipt:alert(1)") { "XSS" }
				a(href: "javascri\tpt:alert(1)") { "XSS" }
				a(href: "javascrip\tt:alert(1)") { "XSS" }
				a(href: "javascript\t:alert(1)") { "XSS" }
				a(href: "javascript:\talert(1)") { "XSS" }
			end
		end

		it "strips the javascript protocol" do
			expect(output.scan("<a>").size).to be == 12
			expect(output.scan("href").size).to be == 0
		end
	end

	with "naughty javascript link protocol with a hidden newline character" do
		view do
			def view_template
				a(href: "\njavascript:alert(1)") { "XSS" }
				a(href: "j\navascript:alert(1)") { "XSS" }
				a(href: "ja\nvascript:alert(1)") { "XSS" }
				a(href: "jav\nascript:alert(1)") { "XSS" }
				a(href: "java\nscript:alert(1)") { "XSS" }
				a(href: "javas\ncript:alert(1)") { "XSS" }
				a(href: "javasc\nript:alert(1)") { "XSS" }
				a(href: "javascr\nipt:alert(1)") { "XSS" }
				a(href: "javascri\npt:alert(1)") { "XSS" }
				a(href: "javascrip\nt:alert(1)") { "XSS" }
				a(href: "javascript\n:alert(1)") { "XSS" }
				a(href: "javascript:\nalert(1)") { "XSS" }
			end
		end

		it "strips the javascript protocol" do
			expect(output.scan("<a>").size).to be == 12
			expect(output.scan("href").size).to be == 0
		end
	end

	with "naughty javascript link protocol with a hidden whitespace character" do
		view do
			def view_template
				a(href: " javascript:alert(1)") { "XSS" }
				a(href: "j avascript:alert(1)") { "XSS" }
				a(href: "ja vascript:alert(1)") { "XSS" }
				a(href: "jav ascript:alert(1)") { "XSS" }
				a(href: "java script:alert(1)") { "XSS" }
				a(href: "javas cript:alert(1)") { "XSS" }
				a(href: "javasc ript:alert(1)") { "XSS" }
				a(href: "javascr ipt:alert(1)") { "XSS" }
				a(href: "javascri pt:alert(1)") { "XSS" }
				a(href: "javascrip t:alert(1)") { "XSS" }
				a(href: "javascript :alert(1)") { "XSS" }
				a(href: "javascript: alert(1)") { "XSS" }
			end
		end

		it "strips the javascript protocol" do
			expect(output.scan("<a>").size).to be == 12
			expect(output.scan("href").size).to be == 0
		end
	end