Red Hat Enterprise Linux 8 update for samba

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

Install updates from vendor's website.

Vulnerable software versions

Red Hat CodeReady Linux Builder for IBM z Systems: 8.0

Red Hat CodeReady Linux Builder for ARM 64: 8.0

Red Hat CodeReady Linux Builder for Power, little endian: 8.0

Red Hat CodeReady Linux Builder for x86_64: 8.0

Red Hat Enterprise Linux for ARM 64: 8

Red Hat Enterprise Linux for Power, little endian: 8

Red Hat Enterprise Linux for IBM z Systems: 8

Red Hat Enterprise Linux for x86_64: 8.0

samba (Red Hat package): before 4.14.5-2.el8

CPE2.3

• cpe:2.3:o:red_hat:red_hat_codeready_linux_builder_for_ibm_z_systems:8.0:*:*:*:*:*:*:*
• cpe:2.3:o:red_hat:red_hat_codeready_linux_builder_for_arm_64:8.0:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_codeready_linux_builder_for_power_little_endian:8.0:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_codeready_linux_builder_for_x86_64:8.0:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_arm_64:8:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_power_little_endian:8:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_ibm_z_systems:8:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux:8.0:*:*:*:*:*:*:*
• cpe:2.3:a:red_hat:samba_redhat_package:*:*:*:*:*:red_hat_enterprise_linux:*:*

External links

https://access.redhat.com/errata/RHBA-2021:4438

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.