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GHSA-xq52-rv6w-397c
No affected components available
Impact
If user-supplied input was passed into append/override_content_security_policy_directives, a semicolon could be injected leading to directive injection.
This could be used to e.g. override a script-src directive. Duplicate directives are ignored and the first one wins. The directives in secure_headers are sorted alphabetically so they pretty much all come before script-src. A previously undefined directive would receive a value even if SecureHeaders::OPT_OUT was supplied.
The fixed versions will silently convert the semicolons to spaces and emit a deprecation warning when this happens. This will result in innocuous browser console messages if being exploited/accidentally used. In future releases, we will raise application errors resulting in 500s.
Duplicate script-src directives detected. All but the first instance will be ignored.
See https://www.w3.org/TR/CSP3/#parse-serialized-policy
Note: In this case, the user agent SHOULD notify developers that a duplicate directive was ignored. A console warning might be appropriate, for example.
Patches
Depending on what major version you are using, the fixed versions are 6.2.0, 5.1.0, 3.8.0.
Workarounds
If you are passing user input into the above methods, you could filter out the input:
override_content_security_policy_directives(:frame_src, [user_input.gsub(";", " ")])
References
Reported in https://github.com/twitter/secure_headers/issues/418 https://www.w3.org/TR/CSP3/#parse-serialized-policy
For more information
If you have any questions or comments about this advisory:
- Open an issue in this repo
- DM @ndm on twitter
The vulnerability can be exploited over the network without needing physical access. It is difficult for an attacker to exploit this vulnerability and may require special conditions. An attacker needs basic access or low-level privileges. The attacker needs the user to perform some action, like clicking a link. The vulnerability can affect other systems as well, not just the initial system. There is a low impact on the confidentiality of the information. There is a low impact on the integrity of the data.
Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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