User redirection via incomplete Host validation
Published Feb 11, 2021 · Updated Aug 3, 2024
Open redirect in Rails Action Pack 6.0.0 through 6.0.3.4 and 6.1.0 through 6.1.2 allows remote attackers to redirect users via crafted Host headers. The authorized? method removes only a trailing port before matching the entire Host value against a leading-dot host permission, allowing an invalid delimiter and matching suffix to pass the allowlist. Exploitation requires a leading-dot allowed-host entry and user interaction; the victim is redirected to an attacker-controlled site, enabling phishing without reported server-side data modification or interruption.
Summary
What happened
Open redirect in Rails Action Pack 6.0.0 through 6.0.3.4 and 6.1.0 through 6.1.2 allows remote attackers to redirect users via crafted Host headers. The authorized? method removes only a trailing port before matching the entire Host value against a leading-dot host permission, allowing an invalid delimiter and matching suffix to pass the allowlist. Exploitation requires a leading-dot allowed-host entry and user interaction; the victim is redirected to an attacker-controlled site, enabling phishing without reported server-side data modification or interruption.
The record
- CVE
- CVE-2021-22881
- Published
- Feb 11, 2021
- Updated
- Aug 3, 2024
- Vendor
- Rails
- Product
- Action Pack
- Classifications
- CWE-601, T1566.002
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 11, 2021CVE publishedPublication date reported by the CVE source.
- Aug 3, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=Fixed in 6.1.2.1, 6.0.3.5
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Rails Host Authorization crafted-Host regression caseproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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