Bug 2357212

Summary:	Disallow RC4 HMAC-MD5 session keys by default [fedora]
Product:	[Fedora] Fedora	Reporter:	Julien Rische <jrische>
Component:	krb5	Assignee:	Julien Rische <jrische>
Status:	CLOSED DUPLICATE	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	medium	Docs Contact:
Priority:	unspecified
Version:	rawhide	CC:	abokovoy, antorres, ftrivino, jrische, j, sbose, ssorce
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Hardware:	Unspecified
OS:	Linux
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Last Closed:	2025-04-15 09:30:32 UTC	Type:	---
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Description Julien Rische 2025-04-03 14:46:55 UTC

As explained in the section "The problem with RC4-HMAC" of the following document, using the arcfour-hmac-md5 as encryption type for session keys is vulnerable to attacks based on MD5 collision:
https://i.blackhat.com/EU-22/Thursday-Briefings/EU-22-Tervoort-Breaking-Kerberos-RC4-Cipher-and-Spoofing-Windows-PACs-wp.pdf

This encryption type should be disallowed for session keys by default.

Reproducible: Always

Comment 1 Julien Rische 2025-04-15 09:30:32 UTC


*** This bug has been marked as a duplicate of bug 2359672 ***

Comment 2 Julien Rische 2025-04-15 09:31:28 UTC


*** This bug has been marked as a duplicate of bug 2359705 ***