Kerberos
TMA-KERBEROS-KRB5-ENCTYPES
Ensure krb5.conf does not permit DES, 3DES or RC4 encryption types
HighLevel 1Automatedkerberos
Description
permitted_enctypes, default_tkt_enctypes and default_tgs_enctypes in /etc/krb5.conf control which session and ticket enctypes the KDC host and its clients negotiate. The audit fails if any of them names a des, des3, rc4 or arcfour type.
How it is checked
Audit method: File pattern
- File
/etc/krb5.conf- Pattern
(?mi)^\s*(permitted_enctypes|default_tkt_enctypes|default_tgs_enctypes)\s*=.*(des|rc4|arcfour)
How it is fixed
Fix method: Guidance or infrastructure patch
In [libdefaults] of /etc/krb5.conf remove weak types or set permitted_enctypes = aes256-cts-hmac-sha1-96 aes128-cts-hmac-sha1-96 (plus aes256-cts-hmac-sha384-192 aes128-cts-hmac-sha256-128 where supported). Verify that all clients and services have AES keys before deploying.
Properties
- Operating systems
- Any
- Tags
- kerberoscrypto
- Reference
- CIS MIT Kerberos / Linux Benchmark guidance - Strong Kerberos encryption types (verify section number for your release)
Check this host
Run this on a machine you are allowed to audit. The scan is read-only.
shell
tmaegis scan --target kerberos