Internet Bug Bounty: Rack CVE-2022-30122: Denial of Service Vulnerability in Rack Multipart Parsing

2022-07-0522:59:39

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hackerone.com

$2400

7.5 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

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

5 Medium

CVSS2

Access Vector

NETWORK

Access Complexity

LOW

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

PARTIAL

AV:N/AC:L/Au:N/C:N/I:N/A:P

0.0004 Low

EPSS

Percentile

10.4%

JSON

ReDoS in Rack::Multipart::BROKEN_QUOTED and Rack::Multipart::BROKEN_UNQUOTED.

https://groups.google.com/g/ruby-security-ann/c/L2Axto442qk
> Carefully crafted multipart POST requests can cause Rack’s multipart parser to take much longer than expected, leading to a possible denial of service vulnerability.

Impact

When the client sends a specially crafted header, it occur ReDoS on the server side.
Servers that interpret Post data by default, like Rails, are affected.