Oversized uploads via unsigned Content-Length
Published Jun 19, 2020 · Updated Aug 4, 2024
Client-side security enforcement in Ruby on Rails ActiveStorage allows remote attackers to bypass S3 direct-upload size limits. The S3 adapter creates a presigned PUT URL without binding Content-Length to the signature, so the client can change the header after authorization. Only applications using ActiveStorage S3 direct uploads are exposed, and unauthenticated users can store objects larger than server policy permits.
Summary
What happened
Client-side security enforcement in Ruby on Rails ActiveStorage allows remote attackers to bypass S3 direct-upload size limits. The S3 adapter creates a presigned PUT URL without binding Content-Length to the signature, so the client can change the header after authorization. Only applications using ActiveStorage S3 direct uploads are exposed, and unauthenticated users can store objects larger than server policy permits.
The record
- CVE
- CVE-2020-8162
- Published
- Jun 19, 2020
- Updated
- Aug 4, 2024
- Vendor
- Ruby on Rails
- Product
- Ruby on Rails
- Classifications
- CWE-602, CWE-434, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 19, 2020CVE publishedPublication date reported by the CVE source.
- Aug 4, 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?
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- Affected versionversion=rails >= 5.2.4.3, rails >= 6.0.3.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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