CVE-2024-32970 Cross-site Scripting (XSS) possible with maliciously formed HTML attribute names and values in Phlex
Attackers can execute arbitrary JavaScript via malicious HTML attributes in Phlex views, requiring upgrades or CSP configuration.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2024-32970?
CVE-2024-32970 is a high-severity cross-site scripting vulnerability in phlex-ruby phlex, published on 30 Apr 2024. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Phlex is a framework for building object-oriented views in Ruby. In affected versions there is a potential cross-site scripting (XSS) vulnerability that can be exploited via maliciously crafted user data. Since the last two vulnerabilities https://github.com/phlex-ruby/phlex/security/advisories/GHSA-242p-4v39-2v8g and https://github.com/phlex-ruby/phlex/security/advisories/GHSA-g7xq-xv8c-h98c, we have invested in extensive browser tests. It was these new tests that helped us uncover these issues. As of now the project exercises every possible attack vector the developers can think of — including enumerating every ASCII character, and we run these tests in Chrome, Firefox and Safari. Additionally, we test against a list of 6613 known XSS payloads (see: payloadbox/xss-payload-list). The reason these issues were not detected before is the escapes were working as designed. However, their design didn't take into account just how recklessly permissive browsers are when it comes to executing unsafe JavaScript via HTML attributes. If you render an `<a>` tag with an `href` attribute set to a user-provided link, that link could potentially execute JavaScript when clicked by another user. If you splat user-provided attributes when rendering any HTML or SVG tag, malicious event attributes could be included in the output, executing JavaScript when the events are triggered by another user. Patches are available on RubyGems for all minor versions released in the last year. Users are advised to upgrade. Users unable to upgrade should configure a Content Security Policy that does not allow `unsafe-inline` which would effectively prevent this vulnerability from being exploited. Users who upgrade are also advised to configure a Content Security Policy header that does not allow `unsafe-inline`.
Weakness: CWE-79
Which versions are affected by CVE-2024-32970?
4 open source packages ship an affected version, including phlex.
| Package | Affected | Fixed in |
|---|---|---|
phlex RubyGems | All versions | 1.9.3 |
phlex RubyGems | All versions | 1.9.3 |
phlex RubyGems | From 1.10.0 | 1.10.2 |
phlex RubyGems | From 1.10.0 | 1.10.2 |
How do I fix CVE-2024-32970?
Upgrade phlex to a fixed version for your release line: 1.9.3 or 1.10.2.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2024-32970 being exploited?
There is no known exploitation of CVE-2024-32970 in the wild and no public exploit code.
Sources
Also known as GHSA-9p57-h987-4vgx.