CVE-2018-20217: Medium severity kerberos vulnerability

Published Dec 26, 2018
·
Updated

A Reachable Assertion issue was discovered in the KDC in MIT Kerberos 5 (aka krb5) before 1.17. If an attacker can obtain a krbtgt ticket using an older encryption type (single-DES, triple-DES, or RC4), the attacker can crash the KDC by making an S4U2Self request.

Affected Software

3 affected components
MIT Kerberos<5-1.17
Debian Debian Linux=8.0
Debian Debian Linux=9.0

Event History

Dec 26, 2018
CVE Published
via MITRE·08:00 PM
Data Sourced
via MITRE·08:00 PM
Description
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Frequently Asked Questions

1

What is CVE-2018-20217?

CVE-2018-20217 is a vulnerability in MIT Kerberos 5 (krb5) before version 1.17 that allows an attacker with a krbtgt ticket using an older encryption type to crash the KDC by making an S4U2Self request.

2

How does CVE-2018-20217 affect MIT Kerberos?

CVE-2018-20217 affects MIT Kerberos 5 (krb5) before version 1.17 by causing a crash in the KDC if an attacker can obtain a krbtgt ticket with an older encryption type.

3

What is the severity of CVE-2018-20217?

CVE-2018-20217 has a severity rating of 5.3 (medium).

4

How can I fix CVE-2018-20217 in MIT Kerberos?

To fix CVE-2018-20217 in MIT Kerberos, update to version 1.17 or later.

5

Are there any references for CVE-2018-20217?

Yes, here are some references for CVE-2018-20217: [MIT Kerberos RT Ticket](http://krbdev.mit.edu/rt/Ticket/Display.html?id=8763), [MIT Kerberos Commit](https://github.com/krb5/krb5/commit/5e6d1796106df8ba6bc1973ee0917c170d929086), [Debian LTS Announcement](https://lists.debian.org/debian-lts-announce/2019/01/msg00020.html).

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