Ubuntu update for samba

Published: 2022-02-01 | Updated: 2022-09-22

Risk	High
Patch available	YES
Number of vulnerabilities	3
CVE-ID	CVE-2021-43566 CVE-2021-44142 CVE-2022-0336
CWE-ID	CWE-59 CWE-787 CWE-345
Exploitation vector	Network
Public exploit	Public exploit code for vulnerability #2 is available.
Vulnerable software	Ubuntu Operating systems & Components / Operating system samba (Ubuntu package) Operating systems & Components / Operating system package or component
Vendor	Canonical Ltd.

Security Bulletin

This security bulletin contains information about 3 vulnerabilities.

1) Link following

EUVDB-ID: #VU59345

Risk: Low

CVSSv4.0: 0.5 [CVSS:4.0/AV:A/AC:L/AT:P/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-43566

CWE-ID: CWE-59 - Improper Link Resolution Before File Access ('Link Following')

Exploit availability: No

Description

The vulnerability allows a remote user to bypass implemented security restrictions.

The vulnerability exists due to a symlink race condition when creating directories. A remote authenticated user can use SMB1 or NFS symlink race to create directories on the Unix filesystem outside of the share definition.

Successful exploitation of the vulnerability requites that the user has permissions to create folder in the target directory.

Mitigation

Update the affected package samba to the latest version.

Vulnerable software versions

Ubuntu: 20.04 - 21.10

samba (Ubuntu package): before 2:4.13.17~dfsg-0ubuntu0.21.04.1

CPE2.3

External links

https://ubuntu.com/security/notices/USN-5260-1

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the local network (LAN).

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.

2) Out-of-bounds write

EUVDB-ID: #VU60186

Risk: High

CVSSv4.0: 8.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P/U:Amber]

CVE-ID: CVE-2021-44142

CWE-ID: CWE-787 - Out-of-bounds write

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a boundary error when processing EA metadata while opening files in smbd within the VFS Samba module (vfs_fruit). A remote attacker with ability to write to file's extended attributes can trigger an out-of-bounds write and execute arbitrary code with root privileges.

Note, the vulnerability in vfs_fruit exists in the default configuration of the fruit VFS module using fruit:metadata=netatalk or fruit:resource=file.

Mitigation

Update the affected package samba to the latest version.

Vulnerable software versions

Ubuntu: 20.04 - 21.10

samba (Ubuntu package): before 2:4.13.17~dfsg-0ubuntu0.21.04.1

CPE2.3

cpe:2.3:o:canonical:samba_ubuntu_package:*:*:*:*:*:ubuntu:*:*

External links

https://ubuntu.com/security/notices/USN-5260-1

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.

3) Insufficient verification of data authenticity

EUVDB-ID: #VU60185

Risk: Low

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2022-0336

CWE-ID: CWE-345 - Insufficient Verification of Data Authenticity

Exploit availability: No

Description

The vulnerability allows a local user to impersonate arbitrary services.

The vulnerability exists due to Samba AD DC relies only on SPN (service principals name) to identify services on the network. An attacker with ability to modify SPNs can bypass implemented protection and cause a denial of service condition by adding an SPN that matches an existing service or impersonate services on the network.

Mitigation

Update the affected package samba to the latest version.

Vulnerable software versions

Ubuntu: 20.04 - 21.10

samba (Ubuntu package): before 2:4.13.17~dfsg-0ubuntu0.21.04.1

CPE2.3

cpe:2.3:o:canonical:samba_ubuntu_package:*:*:*:*:*:ubuntu:*:*

External links

https://ubuntu.com/security/notices/USN-5260-1

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated privileged user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.