Red Hat update for samba

1) Man-in-the-Middle attack

EUVDB-ID: #VU8516

Risk: Low

CVSSv4.0: 1.3 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2017-12150

CWE-ID: CWE-310 - Cryptographic Issues

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform MitM attack.

The vulnerability exists due to several Samba tools do not require signing for SMB connections. The affected tools are:
- 'smb2mount -e', 'smbcacls -e' and 'smbcquotas -e',;
- the python binding exported as 'samba.samba3.libsmb_samba_internal' doesn't make use of the "client signing" smb.conf option;
- libgpo as well as 'net ads gpo' doesn't require SMB signing when fetching group policies
- commandline tools like 'smbclient', 'smbcacls' and 'smbcquotas' allow a fallback to an anonymous connection when using the '--use-ccache' option and this happens even if SMB signing is required.

Successful exploitation of the vulnerability may allow an attacker to perform MitM attack and gain access to potentially sensitive information or elevate privileges on the server.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for Scientific Computing: 6

Red Hat Enterprise Linux for IBM z Systems: 6

Red Hat Enterprise Linux Desktop: 6

Red Hat Enterprise Linux Workstation: 6

Red Hat Enterprise Linux Server: 6.0

CPE2.3

• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_scientific_computing:6:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_ibm_z_systems:6:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_desktop:6:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_workstation:6:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_server:6.0:*:*:*:*:red_hat_enterprise_linux:*:*

External links

https://access.redhat.com/errata/RHSA-2017:2789

Q & A

Can this vulnerability be exploited remotely?

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

Is there known malware, which exploits this vulnerability?

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

2) Memory leak

EUVDB-ID: #VU8518

Risk: Low

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

CVE-ID: CVE-2017-12163

CWE-ID: CWE-401 - Missing release of memory after effective lifetime

Exploit availability: No

Description

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to memory information leak over SMB1. A client with write access to a share can cause server memory contents to be written into a file or printer. Some SMB1 write requests were not correctly range checked to ensure the client had sent enough data to fulfill the write, allowing server memory contents to be written into the file (or printer) instead of client supplied data. The client cannot control the area of the server memory that is written to the file (or printer).

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for Scientific Computing: 6

Red Hat Enterprise Linux for IBM z Systems: 6

Red Hat Enterprise Linux Desktop: 6

Red Hat Enterprise Linux Workstation: 6

Red Hat Enterprise Linux Server: 6.0

CPE2.3

• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_scientific_computing:6:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_ibm_z_systems:6:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_desktop:6:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_workstation:6:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_server:6.0:*:*:*:*:red_hat_enterprise_linux:*:*

External links

https://access.redhat.com/errata/RHSA-2017:2789

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.

3) Race condition

EUVDB-ID: #VU6630

Risk: Low

CVSSv4.0: 2.1 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P/U:Clear]

CVE-ID: CVE-2017-2619

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Exploit availability: Yes

Description

The vulnerability allows a remote authenticated user to access otherwise restricted files.

The vulnerability exists due to a race condition when processing symlinks, which lead to files outside the shared folder. An attacker with ability to crate a symlink on a network share can access files not exported under the share definition.

Successful exploitation of the vulnerability may allow an attacker to gain access to potentially sensitive data, but requires that server is under heavy load.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for Scientific Computing: 6

Red Hat Enterprise Linux for IBM z Systems: 6

Red Hat Enterprise Linux Desktop: 6

Red Hat Enterprise Linux Workstation: 6

Red Hat Enterprise Linux Server: 6.0

CPE2.3

• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_scientific_computing:6:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_ibm_z_systems:6:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_desktop:6:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_workstation:6:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_server:6.0:*:*:*:*:red_hat_enterprise_linux:*:*

External links

https://access.redhat.com/errata/RHSA-2017:2789

Q & A

Can this vulnerability be exploited remotely?

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

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.