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Security Advisories: MDE2OlNlY3VyaXR5QWR2aXNvcnlHSFNBLTZoZnEtaDhocS04N21m

HTTP Request Smuggling in hyper

Summary

hyper's HTTP server code had a flaw that incorrectly understands some requests with multiple transfer-encoding headers to have a chunked payload, when it should have been rejected as illegal. This combined with an upstream HTTP proxy that understands the request payload boundary differently can result in "request smuggling" or "desync attacks".

Vulnerability

The flaw was introduced in https://github.com/hyperium/hyper/commit/26417fc24a7d05df538e0f39239b373c5c3d61f6, released in v0.12.0.

Consider this example request:

POST /yolo HTTP/1.1
Transfer-Encoding: chunked
Transfer-Encoding: cow

This request should be rejected, according to RFC 7230, since it has a Transfer-Encoding header, but after folding, it does not end in chunked. hyper would notice the chunked in the first line, and then check the second line, and thanks to a missing boolean assignment, not set the error condition. hyper would treat the payload as being chunked. By differing from the spec, it is possible to send requests like these to endpoints that have different HTTP implementations, with different interpretations of the payload semantics, and cause "desync attacks".

There are several parts of the spec that must also be checked, and hyper correctly handles all of those. Additionally, hyper's client does not allow sending requests with improper headers, so the misunderstanding cannot be propagated further.

Read more about desync attacks: https://portswigger.net/research/http-desync-attacks-request-smuggling-reborn

Impact

To determine if vulnerable, all these things must be true:

Patches

We have released and backported the following patch versions:

Workarounds

Besides upgrading hyper, you can take the following options:

Credits

This issue was initially reported by ZeddYu Lu From Qi An Xin Technology Research Institute.

Permalink: https://github.com/advisories/GHSA-6hfq-h8hq-87mf
JSON: https://advisories.ecosyste.ms/api/v1/advisories/MDE2OlNlY3VyaXR5QWR2aXNvcnlHSFNBLTZoZnEtaDhocS04N21m
Source: GitHub Advisory Database
Origin: Unspecified
Severity: Moderate
Classification: General
Published: over 2 years ago
Updated: about 1 year ago


CVSS Score: 4.8
CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

Identifiers: GHSA-6hfq-h8hq-87mf, CVE-2021-21299
References: Repository: https://github.com/hyperium/hyper

Affected Packages

cargo:hyper
Dependent packages: 3,673
Dependent repositories: 38,106
Downloads: 134,212,244 total
Affected Version Ranges: >= 0.12.0, < 0.12.36, >= 0.13.0, < 0.13.10, >= 0.14.0, < 0.14.3
Fixed in: 0.12.36, 0.13.10, 0.14.3
All affected versions: 0.12.0, 0.12.1, 0.12.2, 0.12.3, 0.12.4, 0.12.5, 0.12.6, 0.12.7, 0.12.8, 0.12.9, 0.12.10, 0.12.11, 0.12.12, 0.12.13, 0.12.14, 0.12.15, 0.12.16, 0.12.17, 0.12.18, 0.12.19, 0.12.20, 0.12.21, 0.12.22, 0.12.23, 0.12.24, 0.12.25, 0.12.26, 0.12.27, 0.12.28, 0.12.29, 0.12.30, 0.12.31, 0.12.32, 0.12.33, 0.12.34, 0.12.35, 0.13.0, 0.13.1, 0.13.2, 0.13.3, 0.13.4, 0.13.5, 0.13.6, 0.13.7, 0.13.8, 0.13.9, 0.14.0, 0.14.1, 0.14.2
All unaffected versions: 0.0.1, 0.0.2, 0.0.3, 0.0.4, 0.0.5, 0.0.6, 0.0.7, 0.0.8, 0.0.9, 0.0.10, 0.0.11, 0.0.12, 0.0.13, 0.0.14, 0.0.15, 0.0.16, 0.0.17, 0.0.18, 0.0.19, 0.0.20, 0.0.21, 0.1.0, 0.1.1, 0.1.2, 0.1.3, 0.1.4, 0.1.5, 0.1.6, 0.1.7, 0.1.8, 0.1.9, 0.1.10, 0.1.11, 0.1.12, 0.1.13, 0.2.0, 0.2.1, 0.3.0, 0.3.1, 0.3.2, 0.3.3, 0.3.4, 0.3.5, 0.3.6, 0.3.7, 0.3.8, 0.3.9, 0.3.10, 0.3.11, 0.3.12, 0.3.13, 0.3.14, 0.3.15, 0.3.16, 0.4.0, 0.5.0, 0.5.1, 0.5.2, 0.6.0, 0.6.1, 0.6.2, 0.6.3, 0.6.4, 0.6.5, 0.6.6, 0.6.7, 0.6.8, 0.6.9, 0.6.10, 0.6.11, 0.6.12, 0.6.13, 0.6.14, 0.6.15, 0.6.16, 0.7.0, 0.7.1, 0.7.2, 0.8.0, 0.8.1, 0.9.0, 0.9.1, 0.9.2, 0.9.3, 0.9.4, 0.9.5, 0.9.6, 0.9.7, 0.9.8, 0.9.9, 0.9.10, 0.9.11, 0.9.12, 0.9.13, 0.9.14, 0.9.15, 0.9.17, 0.9.18, 0.10.0, 0.10.1, 0.10.2, 0.10.3, 0.10.4, 0.10.5, 0.10.6, 0.10.7, 0.10.8, 0.10.9, 0.10.10, 0.10.11, 0.10.12, 0.10.13, 0.10.14, 0.10.15, 0.10.16, 0.11.0, 0.11.1, 0.11.2, 0.11.3, 0.11.4, 0.11.5, 0.11.6, 0.11.7, 0.11.8, 0.11.9, 0.11.10, 0.11.11, 0.11.12, 0.11.13, 0.11.14, 0.11.15, 0.11.16, 0.11.17, 0.11.18, 0.11.19, 0.11.20, 0.11.21, 0.11.22, 0.11.23, 0.11.24, 0.11.25, 0.11.26, 0.11.27, 0.12.36, 0.13.10, 0.14.3, 0.14.4, 0.14.5, 0.14.6, 0.14.7, 0.14.8, 0.14.9, 0.14.10, 0.14.11, 0.14.12, 0.14.13, 0.14.14, 0.14.15, 0.14.16, 0.14.17, 0.14.18, 0.14.19, 0.14.20, 0.14.21, 0.14.22, 0.14.23, 0.14.24, 0.14.25, 0.14.26, 0.14.27, 0.14.28, 1.0.0, 1.0.1, 1.1.0, 1.2.0