CVE-2020-25721 - log back

CVE-2020-25721 edited at 09 Nov 2021 20:52:43
Severity
- Unknown
+ Medium
Remote
- Unknown
+ Remote
Type
- Unknown
+ Privilege escalation
Description
+ A security issue has been found in Samba versions 4.0.0 to 4.15.1. Samba as an AD DC did not provide a way for Linux applications to obtain a reliable SID (and samAccountName) in issued tickets.
References
+ https://www.samba.org/samba/security/CVE-2020-25721.html
+ https://www.samba.org/samba/ftp/patches/security/samba-4.15.1-security-2021-11-09.patch
Notes
+ Workaround
+ ==========
+
+ It would be prudent to pre-create disabled users in Active Directory matching on all privileged names not held in Active Directory, eg
+
+ samba-tool user add root -H ldap://$SERVER -U$USERNAME%$PASSWORD --random-password
+ samba-tool user add ubuntu -H ldap://$SERVER -U$USERNAME%$PASSWORD --random-password
+ ...
+ (repeat for eg all system users under 1000 in /etc/passwd or special to any other AD-connected services, eg perhaps "admin" for a web-app)
+
+ If running a Microsoft Windows Active Directory, setting ms-DS-MachineAccountQuota to 0, in the Active Directory domain would be advised, if possible.
CVE-2020-25721 created at 09 Nov 2021 20:36:10