Bug 1610640 (CVE-2018-10918)

Summary:	CVE-2018-10918 samba: DsCrackNames on a user without an SPN can trigger NULL-pointer de-reference
Product:	[Other] Security Response	Reporter:	Sam Fowler <sfowler>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	abhgupta, abokovoy, anoopcs, asn, bmcclain, dbaker, dblechte, dfediuck, eedri, gdeschner, jarrpa, jokerman, jstephen, lmohanty, madam, mgoldboi, michal.skrivanek, rhs-smb, sankarshan, sbonazzo, sbose, security-response-team, sherold, sisharma, ssaha, ssorce, sthangav, trankin, vbellur
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	samba 4.7.9, samba 4.8.4	Doc Type:	If docs needed, set a value
Doc Text:	A null pointer dereference flaw was found in the way samba checked database outputs from the LDB database layer. An authenticated attacker could use this flaw to crash a samba server in an Active Diretory Domain Controller configuration.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2019-06-10 10:34:42 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1612807, 1617910, 1617913
Bug Blocks:	1610646

Description Sam Fowler 2018-08-01 05:29:33 UTC

As per upstream advisory:

All versions of Samba from 4.7.0 onwards are vulnerable to a denial of service attack which can crash the "samba" process when Samba is an Active Directory Domain Controller.

Missing database output checks on the returned directory attributes from the LDB database layer cause the DsCrackNames call in the DRSUAPI server to crash when following a NULL pointer.

This call is only available after authentication.

There is no further vulnerability associated with this error, merely a denial of service.

Comment 2 Sam Fowler 2018-08-16 03:39:27 UTC

External Reference:

https://www.samba.org/samba/security/CVE-2018-10918.html

Comment 3 Sam Fowler 2018-08-16 07:13:22 UTC

Created samba tracking bugs for this issue:

Affects: fedora-all [bug 1617910]

Comment 5 Huzaifa S. Sidhpurwala 2018-08-17 05:38:30 UTC

Acknowledgments:

Name: Volker Mauel (the Samba project)