Bug 2359465 (CVE-2025-3576)

Summary: CVE-2025-3576 krb5: Kerberos RC4-HMAC-MD5 Checksum Vulnerability Enabling Message Spoofing via MD5 Collisions
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: abokovoy, brking, davidn, haoli, hkataria, jajackso, jcammara, jmitchel, jneedle, jrische, kegrant, koliveir, kshier, mabashia, pbraun, security-response-team, shvarugh, simaishi, smcdonal, stcannon, teagle, tfister, thavo, yguenane
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A vulnerability in the MIT Kerberos implementation allows GSSAPI-protected messages using RC4-HMAC-MD5 to be spoofed due to weaknesses in the MD5 checksum design. If RC4 is preferred over stronger encryption types, an attacker could exploit MD5 collisions to forge message integrity codes. This may lead to unauthorized message tampering.
 Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 2359672, 2359673, 2359705    
Bug Blocks:    
Deadline: 2025-04-14   

Description OSIDB Bzimport 2025-04-14 11:06:28 UTC 
Under specific configurations where RC4-HMAC-MD5 is negotiated for GSSAPI-secured communication, attackers can sniff messages and use MD5 collision techniques to craft altered messages that retain the same MIC (Message Integrity Code). The vulnerable checksum function from RFC4757 allows this due to its flawed use of MD5. The attack relies on RC4 being chosen over stronger encryption options and presumes attacker access to the network traffic.
Comment 3 errata-xmlrpc 2025-06-03 01:22:19 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2025:8411 https://access.redhat.com/errata/RHSA-2025:8411