Samba-4.13.1 (Security Release)
|Reported by:||Douglas R. Reno||Owned by:||Douglas R. Reno|
New point version
Release Announcements --------------------- These are a security releases in order to address the following defects: o CVE-2020-14318: Missing handle permissions check in SMB1/2/3 ChangeNotify. o CVE-2020-14323: Unprivileged user can crash winbind. o CVE-2020-14383: An authenticated user can crash the DCE/RPC DNS with easily crafted records. ======= Details ======= o CVE-2020-14318: The SMB1/2/3 protocols have a concept of "ChangeNotify", where a client can request file name notification on a directory handle when a condition such as "new file creation" or "file size change" or "file timestamp update" occurs. A missing permissions check on a directory handle requesting ChangeNotify meant that a client with a directory handle open only for FILE_READ_ATTRIBUTES (minimal access rights) could be used to obtain change notify replies from the server. These replies contain information that should not be available to directory handles open for FILE_READ_ATTRIBUTE only. o CVE-2020-14323: winbind in version 3.6 and later implements a request to translate multiple Windows SIDs into names in one request. This was done for performance reasons: Active Directory domain controllers can do multiple SID to name translations in one RPC call. It was an obvious extension to also offer this batch operation on the winbind unix domain stream socket that is available to local processes on the Samba server to reduce network round-trips to the domain controller. Due to improper input validation a hand-crafted packet can make winbind perform a NULL pointer dereference and thus crash. o CVE-2020-14383: Some DNS records (such as MX and NS records) usually contain data in the additional section. Samba's dnsserver RPC pipe (which is an administrative interface not used in the DNS server itself) made an error in handling the case where there are no records present: instead of noticing the lack of records, it dereferenced uninitialised memory, causing the RPC server to crash. This RPC server, which also serves protocols other than dnsserver, will be restarted after a short delay, but it is easy for an authenticated non-admin attacker to crash it again as soon as it returns. The Samba DNS server itself will continue to operate, but many RPC services will not. For more details, please refer to the security advisories. Changes: -------- o Jeremy Allison <firstname.lastname@example.org> * BUG 14434: CVE-2020-14318: s3: smbd: Ensure change notifies can't get set unless the directory handle is open for SEC_DIR_LIST. o Douglas Bagnall <email@example.com> * BUG 12795: CVE-2020-14383: Remote crash after adding NS or MX records using 'samba-tool'. * BUG 14472: CVE-2020-14383: Remote crash after adding MX records. o Volker Lendecke <firstname.lastname@example.org> * BUG 14436: CVE-2020-14323: winbind: Fix invalid lookupsids DoS.
Change History (7)
Note: See TracTickets for help on using tickets.