Detections
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Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS : Samba update (USN-4559-1)
critical Nessus Plugin ID 141112
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Synopsis
The remote Ubuntu host is missing a security update.Description
The remote Ubuntu 16.04 LTS / 18.04 LTS / 20.04 LTS host has packages installed that are affected by a vulnerability as referenced in the USN-4559-1 advisory.Tom Tervoort discovered that the Netlogon protocol implemented by Samba incorrectly handled the authentication scheme. A remote attacker could use this issue to forge an authentication token and steal the credentials of the domain admin.
While a previous security update fixed the issue by changing the server schannel setting to default to yes, instead of auto, which forced a secure netlogon channel, this update provides additional improvements.
For compatibility reasons with older devices, Samba now allows specifying an insecure netlogon configuration per machine. See the following link for examples:
https://www.samba.org/samba/security/CVE-2020-1472.html
In addition, this update adds additional server checks for the protocol attack in the client-specified challenge to provide some protection when 'server schannel = no/auto' and avoid the false-positive results when running the proof-of-concept exploit.
Tenable has extracted the preceding description block directly from the Ubuntu security advisory.
Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.
Solution
Update the affected packages.See Also
Plugin Details
Severity: Critical
ID: 141112
File Name: ubuntu_USN-4559-1.nasl
Version: 1.15
Type: local
Agent: unix
Family: Ubuntu Local Security Checks
Published: 10/2/2020
Updated: 11/29/2024
Supported Sensors: Agentless Assessment, Continuous Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent, Nessus
Risk Information
VPR
Risk Factor: Critical
Score: 10.0
CVSS v2
Risk Factor: High
Base Score: 9.3
Temporal Score: 8.1
Vector: CVSS2#AV:N/AC:M/Au:N/C:C/I:C/A:C
CVSS Score Source: CVE-2020-1472
CVSS v3
Risk Factor: Critical
Base Score: 10
Temporal Score: 9.5
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Temporal Vector: CVSS:3.0/E:H/RL:O/RC:C
Vulnerability Information
CPE: p-cpe:/a:canonical:ubuntu_linux:samba-vfs-modules, p-cpe:/a:canonical:ubuntu_linux:python-samba, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:libpam-winbind, p-cpe:/a:canonical:ubuntu_linux:libparse-pidl-perl, p-cpe:/a:canonical:ubuntu_linux:samba-common, p-cpe:/a:canonical:ubuntu_linux:samba-dev, p-cpe:/a:canonical:ubuntu_linux:libwbclient0, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:samba-common-bin, p-cpe:/a:canonical:ubuntu_linux:libwbclient-dev, p-cpe:/a:canonical:ubuntu_linux:winbind, p-cpe:/a:canonical:ubuntu_linux:samba-dsdb-modules, p-cpe:/a:canonical:ubuntu_linux:python3-samba, p-cpe:/a:canonical:ubuntu_linux:registry-tools, p-cpe:/a:canonical:ubuntu_linux:samba-testsuite, p-cpe:/a:canonical:ubuntu_linux:smbclient, p-cpe:/a:canonical:ubuntu_linux:ctdb, p-cpe:/a:canonical:ubuntu_linux:samba-libs, p-cpe:/a:canonical:ubuntu_linux:libsmbclient, p-cpe:/a:canonical:ubuntu_linux:libnss-winbind, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, p-cpe:/a:canonical:ubuntu_linux:samba, p-cpe:/a:canonical:ubuntu_linux:libsmbclient-dev
Required KB Items: Host/cpu, Host/Ubuntu, Host/Ubuntu/release, Host/Debian/dpkg-l
Exploit Available: true
Exploit Ease: Exploits are available
Patch Publication Date: 9/30/2020
Vulnerability Publication Date: 8/17/2020
CISA Known Exploited Vulnerability Due Dates: 9/21/2020
Reference Information
CVE: CVE-2020-1472