Orpheus' Lyre: Remote Service Impersonation Vulnerability in Heimdal

CVE-2017-11103 · HIGH Severity

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

Heimdal before 7.4 allows remote attackers to impersonate services with Orpheus' Lyre attacks because it obtains service-principal names in a way that violates the Kerberos 5 protocol specification. In _krb5_extract_ticket() the KDC-REP service name must be obtained from the encrypted version stored in 'enc_part' instead of the unencrypted version stored in 'ticket'. Use of the unencrypted version provides an opportunity for successful server impersonation and other attacks. NOTE: this CVE is only for Heimdal and other products that embed Heimdal code; it does not apply to other instances in which this part of the Kerberos 5 protocol specification is violated.

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