Attachment 15884 Details for Bug 14331 – First draft ASQ Advisory

First draft ASQ Advisory

ASQ-security-advisory.txt (text/plain), 2.14 KB, created by Andrew Bartlett on 2020-03-31 22:52:34 UTC

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Creator: Andrew Bartlett

Created: 2020-03-31 22:52:34 UTC

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patch

obsolete

>===========================================================
>== Subject:     Use-after-free in Samba AD DC LDAP Server with ASQ
>==
>== CVE ID#:     
>==
>== Versions:    Samba 4.10.0 and later
>==
>== Summary:     A client combining the 'ASQ' and 'Paged Results' LDAP
>                controls can cause a use-after-free in Samba's AD DC
>		LDAP server
>===========================================================
>
>===========
>Description
>===========
>
>Samba has, since Samba 4.0, supported the Paged Results LDAP feature,
>to allow clients to obtain pages of search results against a Samba AD
>DC using an LDAP control.
>
>Since Samba 4.7.11 and 4.8.6 a Denial of Serivce prevention has been
>in place in this module, to age out old client requests if more than
>10 such requests are outstanding.
>
>A rewrite of the module for more efficint memory handling in Samba
>4.11 changed the module behaviour, and combined with the above to
>introduce the use-after-free.  The use-after-free occours when the
>'Paged Results' control is combined with the 'ASQ' control, another
>Active Directory LDAP feature.
>
>
>==================
>Patch Availability
>==================
>
>Patches addressing both these issues have been posted to:
>
>    https://www.samba.org/samba/security/
>
>Additionally, Samba $VERSIONS have been issued
>as security releases to correct the defect.  Samba administrators are
>advised to upgrade to these releases or apply the patch as soon
>as possible.
>
>==================
>CVSSv3 calculation
>==================
>
>CVSS:3.1:AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:N/A:H (5.3)
>
>=========================
>Workaround or mitigations
>=========================
>
>The crash is hard to trigger, and relies in particular on the chain of
>child and grandchild links being queried with ASQ.  Users without
>write access would have to find a suitable chain within the existing
>directory layout.
>
>=======
>Credits
>=======
>
>Originally reported by Andrei Popa <andrei.popa@next-gen.ro>.
>
>Patches provided by Andrew Bartlett of Catalyst and the Samba team.
>
>==========================================================
>== Our Code, Our Bugs, Our Responsibility.
>== The Samba Team
>==========================================================
>

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