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GHSA-5hq2-xf89-9jxq
No affected components available
There is a possible Open Redirect Vulnerability in Action Pack.
Versions Affected: >= v6.1.0.rc2 Not affected: < v6.1.0.rc2 Fixed Versions: 6.1.3.2
Impact
This is similar to CVE-2021-22881. Specially crafted Host headers in combination with certain "allowed host" formats can cause the Host Authorization middleware in Action Pack to redirect users to a malicious website.
Since rails/rails@9bc7ea5, strings in config.hosts that do not have a leading dot are converted to regular expressions without proper escaping. This causes, for example, config.hosts << "sub.example.com" to permit a request with a Host header value of sub-example.com.
Releases
The fixed releases are available at the normal locations.
Workarounds
The following monkey patch put in an initializer can be used as a workaround.
class ActionDispatch::HostAuthorization::Permissions
def sanitize_string(host)
if host.start_with?(".")
/\A(.+\.)?#{Regexp.escape(host[1..-1])}\z/i
else
/\A#{Regexp.escape host}\z/i
end
end
end
Patches
To aid users who aren't able to upgrade immediately we have provided patches for the two supported release series. They are in git-am format and consist of a single changeset.
- 6-1-open-redirect.patch - Patch for 6.1 series
Please note that only the 6.1.Z, 6.0.Z, and 5.2.Z series are supported at present. Users of earlier unsupported releases are advised to upgrade as soon as possible as we cannot guarantee the continued availability of security fixes for unsupported releases.
Credits
Thanks Jonathan Hefner (https://hackerone.com/jonathanhefner) for reporting this bug!
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. 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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