Red Hat update for Linux Kernel

1) Race condition

EUVDB-ID: #VU9520

Risk: Low

CVSSv4.0: 5.4 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P/U:Clear]

CVE-ID: CVE-2017-1000405

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

Exploit availability: Yes

Description

The vulnerability allows a local user to perform a denial of service (DoS) attack.

The vulnerability exists due to a race condition within touch_pmd() function in mmhugemem.c file when handling THPs. A local user can read read-only huge pages using the get_user_pages() function and overwrite arbitrary huge pages and files mapped via THP.

Successful exploitation of the vulnerability may allow an attacker to perform a denial of service (DoS) attack.

This vulnerability is a result of patch against a another privilege escalation vulnerability in Linux kernel known as Dirty Cow (CVE-2016-5195).

Mitigation

Install update from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for Power 9: 7.0

Red Hat Enterprise Linux for ARM 64: 7.0

:

kernel-alt (Red Hat package): before 4.11.0-44.4.1.el7a

CPE2.3

• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_power_9:7.0:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_arm_64:7.0:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:::::*:*:*:*:*:*:*
• cpe:2.3:o:red_hat:kernel-alt_redhat_package:*:*:*:*:*:red_hat_enterprise_linux:*:*

External links

https://access.redhat.com/errata/RHSA-2018:0180

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

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.

2) Privilege escalation

EUVDB-ID: #VU1039

Risk: Medium

CVSSv4.0: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:A/U:Green]

CVE-ID: CVE-2016-5195

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

Exploit availability: Yes

Description

The vulnerability allows a  local user to obtain elevated privileges on the target system.
The weakness is due to race condition in the kernel memory subsystem in the management of copy-on-write operations on read-only memory mappings that lets attackers to overwrite kernel memory and gain kernel-level privileges.
Successful exploitation of the vulnerability results in gaining of root privileges on the vulnerable system.

Note: the vulnerability was being actively exploited.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux for Power 9: 7.0

Red Hat Enterprise Linux for ARM 64: 7.0

:

kernel-alt (Red Hat package): before 4.11.0-44.4.1.el7a

CPE2.3

• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_power_9:7.0:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_arm_64:7.0:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:::::*:*:*:*:*:*:*
• cpe:2.3:o:red_hat:kernel-alt_redhat_package:*:*:*:*:*:red_hat_enterprise_linux:*:*

External links

https://access.redhat.com/errata/RHSA-2018:0180

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.