Red Hat Enterprise Linux 7 update for kernel

Published: 2019-04-23

Risk	Medium
Patch available	YES
Number of vulnerabilities	2
CVE-ID	CVE-2019-6974 CVE-2019-7221
CWE-ID	CWE-362 CWE-416
Exploitation vector	Local network
Public exploit	Public exploit code for vulnerability #1 is available. Public exploit code for vulnerability #2 is available.
Vulnerable software	Red Hat Enterprise Linux Server - TUS Operating systems & Components / Operating system Red Hat Enterprise Linux for Power, little endian - Extended Update Support Operating systems & Components / Operating system Red Hat Enterprise Linux EUS Compute Node Operating systems & Components / Operating system Red Hat Enterprise Linux for Power, big endian - Extended Update Support Operating systems & Components / Operating system Red Hat Enterprise Linux for IBM z Systems - Extended Update Support Operating systems & Components / Operating system Red Hat Enterprise Linux Server - AUS Operating systems & Components / Operating system Red Hat Enterprise Linux Server - Extended Update Support Operating systems & Components / Operating system Red Hat Enterprise Linux for Power, little endian Operating systems & Components / Operating system Red Hat Enterprise Linux for Power, big endian Operating systems & Components / Operating system Red Hat Enterprise Linux for IBM z Systems Operating systems & Components / Operating system Red Hat Enterprise Linux for Scientific Computing Operating systems & Components / Operating system Red Hat Enterprise Linux Desktop Operating systems & Components / Operating system Red Hat Enterprise Linux Workstation Operating systems & Components / Operating system Red Hat Enterprise Linux Server Operating systems & Components / Operating system Red Hat Virtualization Host Web applications / Remote management & hosting panels kernel (Red Hat package) Operating systems & Components / Operating system package or component
Vendor	Red Hat Inc.

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) Race condition

EUVDB-ID: #VU17555

Risk: Low

CVSSv4.0: 7.4 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Clear]

CVE-ID: CVE-2019-6974

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

Exploit availability: No

Description

The vulnerability allows an adjacent attacker to gain elevated privileges or cause a denial of service (DoS) condition.

The weakness exists due to exists due to a race condition that causes the kvm_ioctl_create_device function, as defined in the virt/kvm/kvm_main.c source code file of the affected software, to improperly handle reference counting. An adjacent attacker can access the system and execute an application that submits malicious input, trigger a use-after-free condition and cause a targeted guest virtual machine to crash, resulting in a DoS condition. In addition, a successful exploit could allow the attacker to gain elevated privileges on a targeted system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Red Hat Enterprise Linux Server - TUS: 7.6

Red Hat Enterprise Linux for Power, little endian - Extended Update Support: 7.6

Red Hat Enterprise Linux EUS Compute Node: 7.6

Red Hat Enterprise Linux for Power, big endian - Extended Update Support: 7.6

Red Hat Enterprise Linux for IBM z Systems - Extended Update Support: 7.6

Red Hat Enterprise Linux Server - AUS: 7.6

Red Hat Enterprise Linux Server - Extended Update Support: 7.6

Red Hat Enterprise Linux for Power, little endian: 7

Red Hat Enterprise Linux for Power, big endian: 7

Red Hat Virtualization Host: 4

Red Hat Enterprise Linux for IBM z Systems: 7

Red Hat Enterprise Linux for Scientific Computing: 7

Red Hat Enterprise Linux Desktop: 7

Red Hat Enterprise Linux Workstation: 7

Red Hat Enterprise Linux Server: 7

kernel (Red Hat package): before 3.10.0-957.12.1.el7

CPE2.3

External links

https://access.redhat.com/errata/RHSA-2019:0818

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.

2) Use-after-free

EUVDB-ID: #VU17760

Risk: Medium

CVSSv4.0: 7.4 [CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/U:Green]

CVE-ID: CVE-2019-7221

CWE-ID: CWE-416 - Use After Free