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Security Advisories: MDE2OlNlY3VyaXR5QWR2aXNvcnlHSFNBLWc2d3EtcWN3bS1qNWcy

Regular Expression Denial of Service in websocket-extensions (RubyGem)

Impact

The ReDoS flaw allows an attacker to exhaust the server's capacity to process incoming requests by sending a WebSocket handshake request containing a header of the following form:

Sec-WebSocket-Extensions: a; b="\c\c\c\c\c\c\c\c\c\c ...

That is, a header containing an unclosed string parameter value whose content is a repeating two-byte sequence of a backslash and some other character. The parser takes exponential time to reject this header as invalid, and this will block the processing of any other work on the same thread. Thus if you are running a single-threaded server, such a request can render your service completely unavailable.

Patches

Users should upgrade to version 0.1.5.

Workarounds

There are no known work-arounds other than disabling any public-facing WebSocket functionality you are operating.

References

Permalink: https://github.com/advisories/GHSA-g6wq-qcwm-j5g2
JSON: https://advisories.ecosyste.ms/api/v1/advisories/MDE2OlNlY3VyaXR5QWR2aXNvcnlHSFNBLWc2d3EtcWN3bS1qNWcy
Source: GitHub Advisory Database
Origin: Unspecified
Severity: High
Classification: General
Published: over 4 years ago
Updated: over 1 year ago


CVSS Score: 8.2
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

EPSS Percentage: 0.00977
EPSS Percentile: 0.83234

Identifiers: GHSA-g6wq-qcwm-j5g2, CVE-2020-7663
References: Repository: https://github.com/faye/websocket-extensions-ruby
Blast Radius: 45.7

Affected Packages

rubygems:websocket-extensions
Dependent packages: 4
Dependent repositories: 378,244
Downloads: 413,720,941 total
Affected Version Ranges: < 0.1.5
Fixed in: 0.1.5
All affected versions: 0.1.0, 0.1.1, 0.1.2, 0.1.3, 0.1.4
All unaffected versions: 0.1.5