NULL pointer dereference in Samba - CVE-2021-3671

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Main Vulnerability Database Vulnerabilities #VU57324

NULL pointer dereference in Samba - CVE-2021-3671

Published: October 13, 2021


Vulnerability identifier: #VU57324
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2021-3671
CWE-ID: CWE-476
Exploitation vector: Adjecent network
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote user to perform a denial of service (DoS) attack.

The vulnerability exists due to a NULL pointer dereference error in the way samba kerberos server handles missing sname attribute in TGS-REQ (Ticket Granting Server - Request). A remote authenticated user can send a specially crafted request to the samba server and perform a denial of service (DoS) attack.


Affected software

Samba
Debian Linux
Fedora
FreeBSD
Ubuntu
openEuler
cflinuxfs3
heimdal
libgssapi3-heimdal (Ubuntu package)
heimdal-servers (Ubuntu package)
libkdc2-heimdal (Ubuntu package)
libkrb5-26-heimdal (Ubuntu package)
heimdal-kdc (Ubuntu package)
heimdal-clients (Ubuntu package)
heimdal-kcm (Ubuntu package)
heimdal-servers-x (Ubuntu package)
heimdal-clients-x (Ubuntu package)
samba (Ubuntu package)
ctdb
samba-krb5-printing
samba-dc
ctdb-tests
samba-debugsource
samba-dc-provision
samba-winbind-modules
python3-samba
samba-winbind
samba
samba-devel
samba-help
samba-common-tools
samba-debuginfo
samba-winbind-krb5-locator
samba-vfs-glusterfs
samba-pidl
samba-common
libsmbclient-devel
samba-client
libwbclient
libwbclient-devel
samba-dc-bind-dlz
samba-test
libsmbclient
samba-libs
samba-winbind-clients
python3-samba-dc
python3-samba-test
heimdal (Debian package)
heimdal

How to mitigate CVE-2021-3671

Install updates from vendor's website.

Samba - addressed in versions 4.13.12, 4.14.8
cflinuxfs3 - update to 0.328.0
heimdal - update to 7.7.1
libgssapi3-heimdal (Ubuntu package) - addressed in versions Ubuntu Pro (Infra-only), 7.5.0+dfsg-1ubuntu0.1, 7.7.0+dfsg-1ubuntu1.1
heimdal-servers (Ubuntu package) - addressed in versions Ubuntu Pro (Infra-only), 7.5.0+dfsg-1ubuntu0.1, 7.7.0+dfsg-1ubuntu1.1
libkdc2-heimdal (Ubuntu package) - addressed in versions Ubuntu Pro (Infra-only), 7.5.0+dfsg-1ubuntu0.1, 7.7.0+dfsg-1ubuntu1.1
libkrb5-26-heimdal (Ubuntu package) - addressed in versions Ubuntu Pro (Infra-only), 7.5.0+dfsg-1ubuntu0.1, 7.7.0+dfsg-1ubuntu1.1
heimdal-kdc (Ubuntu package) - addressed in versions Ubuntu Pro (Infra-only), 7.5.0+dfsg-1ubuntu0.1, 7.7.0+dfsg-1ubuntu1.1
heimdal-clients (Ubuntu package) - addressed in versions Ubuntu Pro (Infra-only), 7.5.0+dfsg-1ubuntu0.1, 7.7.0+dfsg-1ubuntu1.1
heimdal-kcm (Ubuntu package) - addressed in versions Ubuntu Pro (Infra-only), 7.5.0+dfsg-1ubuntu0.1, 7.7.0+dfsg-1ubuntu1.1
heimdal-servers-x (Ubuntu package) - update to Ubuntu Pro (Infra-only)
heimdal-clients-x (Ubuntu package) - update to Ubuntu Pro (Infra-only)
samba (Ubuntu package) - addressed in versions 2:4.7.6+dfsg~ubuntu-0ubuntu2.26, 2:4.7.6+dfsg~ubuntu-0ubuntu2.27, 2:4.13.14+dfsg-0ubuntu0.20.04.1, 2:4.13.14+dfsg-0ubuntu0.20.04.3, 2:4.13.14+dfsg-0ubuntu0.20.04.4, 2:4.13.14+dfsg-0ubuntu0.21.04.1, 2:4.13.14+dfsg-0ubuntu0.21.04.3, 2:4.13.14+dfsg-0ubuntu0.21.04.4, 2:4.13.14+dfsg-0ubuntu0.21.10.1, 2:4.13.14+dfsg-0ubuntu0.21.10.3, 2:4.13.14+dfsg-0ubuntu0.21.10.4
ctdb - update to 4.11.12-6
samba-krb5-printing - update to 4.11.12-6
samba-dc - update to 4.11.12-6
ctdb-tests - update to 4.11.12-6
samba-debugsource - update to 4.11.12-6
samba-dc-provision - update to 4.11.12-6
samba-winbind-modules - update to 4.11.12-6
python3-samba - update to 4.11.12-6
samba-winbind - update to 4.11.12-6
samba - update to 4.11.12-6
samba-devel - update to 4.11.12-6
samba-help - update to 4.11.12-6
samba-common-tools - update to 4.11.12-6
samba-debuginfo - update to 4.11.12-6
samba-winbind-krb5-locator - update to 4.11.12-6
samba-vfs-glusterfs - update to 4.11.12-6
samba-pidl - update to 4.11.12-6
samba-common - update to 4.11.12-6
libsmbclient-devel - update to 4.11.12-6
samba-client - update to 4.11.12-6
libwbclient - update to 4.11.12-6
libwbclient-devel - update to 4.11.12-6
samba-dc-bind-dlz - update to 4.11.12-6
samba-test - update to 4.11.12-6
libsmbclient - update to 4.11.12-6
samba-libs - update to 4.11.12-6
samba-winbind-clients - update to 4.11.12-6
python3-samba-dc - update to 4.11.12-6
python3-samba-test - update to 4.11.12-6
heimdal (Debian package) - update to 7.7.0+dfsg-2+deb11u2
heimdal - addressed in versions 7.7.1-1.el7, 7.7.1-1.el8, 7.7.1-1.fc35, 7.7.1-1.fc36, 7.7.1-1.fc37, 7.7.1-3.fc35, 7.7.1-3.fc36, 7.7.1-3.fc37

External References

Related Security Bulletins