Red Hat update for Linux Kernel

1) Race condition

EUVDB-ID: #VU7694

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-2017-7533

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 execute arbitrary code with escalated privileges.

The vulnerability exists due to a race condition in the fsnotify implementation in the Linux kernel through 4.12.4. A local user can create an application, which leverages simultaneous execution of the inotify_handle_event and vfs_rename functions and trigger memory corruption and denials of service attack or execute arbitrary code on the target system with root privileges.

Successful exploitation of this vulnerability may allow a local user to obtain elevated privileges on the system.

Note: this vulnerability is being active exploited in the wild for 32-bit systems in August 2017.

Mitigation

Install update from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux Server - 4 Year Extended Update Support: 7.3

Red Hat Enterprise Linux Server (for IBM Power LE) - 4 Year Extended Update Support: 7.3

Red Hat Enterprise Linux Server - TUS: 7.3

Red Hat Enterprise Linux for Power, little endian - Extended Update Support: 7.3

Red Hat Enterprise Linux Server - AUS: 7.3

Red Hat Enterprise Linux for Power, big endian - Extended Update Support: 7.3

Red Hat Enterprise Linux for IBM z Systems - Extended Update Support: 7.3

Red Hat Enterprise Linux Server - Extended Update Support: 7.3

kernel (Red Hat package): 3.10.0-123.1.2.el7 - 3.10.0-514.28.2.el7

Red Hat Enterprise Linux EUS Compute Node: 7.3

:

CPE2.3

• cpe:2.3:o:red_hat:red_hat_enterprise_linux_server_-_4_year_extended_update_support:7.3:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_server_for_ibm_power_le_-_4_year_extended_update_support:7.3:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_server_-_tus:7.3:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_power_little_endian_-_extended_update_support:7.3:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_server_-_aus:7.3:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_power_big_endian_-_extended_update_support:7.3:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_ibm_z_systems_-_extended_update_support:7.3:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_server_-_extended_update_support:7.3:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:kernel_redhat_package:3.10.0-123.1.2.el7:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:kernel_redhat_package:3.10.0-123.4.2.el7:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:o:red_hat:red_hat_enterprise_linux_eus_compute_node:7.3:*:*:*:*:red_hat_enterprise_linux:*:*
• cpe:2.3:::::*:*:*:*:*:*:*

External links

https://access.redhat.com/errata/RHSA-2017:2770

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.