Red Hat update for samba

1) Improper authentication

EUVDB-ID: #VU6628

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-2016-2125

CWE-ID: CWE-287 - Improper Authentication

Exploit availability: No

Description

The vulnerability allows a remote attacker on the local network to bypass Kerberos authentication.

The vulnerability exists due to design error when implementing Kerberos authentication. An attacker with access to local network can place a fake Samba server, intercept a valid general purpose Kerberos "Ticket Granting Ticket" (TGT) and fully impersonate the authenticated user or service.

Successful exploitation of the vulnerability may allow an attacker to bypass authentication process and gain access to otherwise restricted resources and services.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for x86_64: 7.0

CPE2.3

• cpe:2.3:o:red_hat:red_hat_enterprise_linux:7.0:*:*:*:*:*:*:*

External links

https://access.redhat.com/errata/RHSA-2017:1265

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) Buffer overflow

EUVDB-ID: #VU6629

Risk: Medium

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

CVE-ID: CVE-2016-2126

CWE-ID: CWE-119 - Memory corruption

Exploit availability: No

Description

The vulnerability allows a remote authenticated attacker to escalate privileges.

The vulnerability exists due to a boundary error within Kerberos PAC validation process in winbindd. A remote authenticated attacker can send a specially crafted request to vulnerable Samba server, trigger buffer overflow and execute arbitrary code on the server with elevated privileges.

Successful exploitation of the vulnerability may allow an attacker to execute arbitrary code with elevated privileges.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for x86_64: 7.0

CPE2.3

• cpe:2.3:o:red_hat:red_hat_enterprise_linux:7.0:*:*:*:*:*:*:*

External links

https://access.redhat.com/errata/RHSA-2017:1265

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 x86_64: 7.0

CPE2.3

• cpe:2.3:o:red_hat:red_hat_enterprise_linux:7.0:*:*:*:*:*:*:*

External links

https://access.redhat.com/errata/RHSA-2017:1265

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.