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Security Advisories: GSA_kwCzR0hTQS02andjLXFyMnEtN3h3as4AA1CM
protocol-http1 HTTP Request/Response Smuggling vulnerability
Impact
RFC 9112 Section 7.1 defined the format of chunk size, chunk data and chunk extension (detailed ABNF is in Appendix section).
In summary:
- The value of Content-Length header should be a string of 0-9 digits.
- The chunk size should be a string of hex digits and should split from chunk data using CRLF.
- The chunk extension shouldn't contain any invisible character.
However, we found that Falcon has following behaviors while disobey the corresponding RFCs.
- Falcon accepts Content-Length header values that have "+" prefix.
- Falcon accepts Content-Length header values that written in hexadecimal with "0x" prefix.
- Falcon accepts "0x" and "+" prefixed chunk size.
- Falcon accepts LF in chunk extension.
This behavior can lead to desync when forwarding through multiple HTTP parsers, potentially results in HTTP request smuggling and firewall bypassing. Note that while these issues were reproduced in Falcon (the server), the issue is with protocol-http1
which implements the HTTP/1 protocol parser. We have not yet been advised of any real world exploit or practical attack.
Patches
Fixed in protocol-http1
v0.15.1+.
Workarounds
None.
References
https://github.com/socketry/protocol-http1/pull/20
Permalink: https://github.com/advisories/GHSA-6jwc-qr2q-7xwjJSON: https://advisories.ecosyste.ms/api/v1/advisories/GSA_kwCzR0hTQS02andjLXFyMnEtN3h3as4AA1CM
Source: GitHub Advisory Database
Origin: Unspecified
Severity: Moderate
Classification: General
Published: 9 months ago
Updated: 6 months ago
CVSS Score: 5.8
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Identifiers: GHSA-6jwc-qr2q-7xwj, CVE-2023-38697
References:
- https://github.com/socketry/protocol-http1/security/advisories/GHSA-6jwc-qr2q-7xwj
- https://github.com/socketry/protocol-http1/pull/20
- https://github.com/socketry/protocol-http1/commit/e11fc164fd2b36f7b7e785e69fa8859eb06bcedd
- https://nvd.nist.gov/vuln/detail/CVE-2023-38697
- https://www.rfc-editor.org/rfc/rfc9112#name-chunked-transfer-coding
- https://github.com/rubysec/ruby-advisory-db/blob/master/gems/protocol-http1/CVE-2023-38697.yml
- https://github.com/advisories/GHSA-6jwc-qr2q-7xwj
Blast Radius: 16.6
Affected Packages
rubygems:protocol-http1
Dependent packages: 3Dependent repositories: 715
Downloads: 5,473,857 total
Affected Version Ranges: < 0.15.1
Fixed in: 0.15.1
All affected versions: 0.1.0, 0.2.0, 0.3.0, 0.4.0, 0.4.1, 0.5.0, 0.6.0, 0.7.0, 0.8.0, 0.8.1, 0.8.2, 0.8.3, 0.9.0, 0.10.0, 0.10.1, 0.10.2, 0.10.3, 0.11.0, 0.11.1, 0.12.0, 0.13.0, 0.13.1, 0.13.2, 0.14.0, 0.14.1, 0.14.2, 0.14.3, 0.14.4, 0.14.6, 0.15.0
All unaffected versions: 0.15.1, 0.16.0, 0.16.1, 0.17.0, 0.18.0, 0.19.0, 0.19.1