Red Hat update for Linux Kernel

Published: 2018-05-08 | Updated: 2018-05-14

Risk	Low
Patch available	YES
Number of vulnerabilities	5
CVE-ID	CVE-2017-16939 CVE-2018-1068 CVE-2018-1087 CVE-2018-8897 CVE-2018-1000199
CWE-ID	CWE-416 CWE-264 CWE-703 CWE-388
Exploitation vector	Local network
Public exploit	Public exploit code for vulnerability #1 is available. Vulnerability #4 is being exploited in the wild.
Vulnerable software Subscribe	kernel-rt (Red Hat package) Operating systems & Components / Operating system package or component Red Hat Enterprise Linux for Real Time Operating systems & Components / Operating system Red Hat Enterprise Linux for Real Time for NFV Operating systems & Components / Operating system
Vendor	Red Hat Inc.

Security Bulletin

This security bulletin contains information about 5 vulnerabilities.

1) Use-after-free error

EUVDB-ID: #VU9601

Risk: Low

CVSSv3.1: 5.9 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2017-16939

CWE-ID: CWE-416 - Use After Free

Exploit availability: Yes

Description

The vulnerability allows a local attacker to cause DoS condition on the target system.

The weakness exists in the XFRM dump policy implementation in net/xfrm/xfrm_user.c in the Linux kernel due to use-after-free error. A local attacker can make a specially crafted SO_RCVBUF setsockopt system call in conjunction with XFRM_MSG_GETPOLICY Netlink messages, trigger memory corruption and cause the service to crash.

Successful exploitation of the vulnerability results in denial of service.

Mitigation

Install update from vendor's website.

Vulnerable software versions

kernel-rt (Red Hat package): 3.10.0-229.1.2.rt56.141.2.el7_1 - 3.10.0-693.rt56.617.el7

Red Hat Enterprise Linux for Real Time: 7

Red Hat Enterprise Linux for Real Time for NFV: 7

CPE2.3

External links

http://access.redhat.com/errata/RHSA-2018:1355

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: #VU11145

Risk: Low

CVSSv3.1: 6.8 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2018-1068

CWE-ID: CWE-264 - Permissions, Privileges, and Access Controls

Exploit availability: No

Description

The vulnerability allows a local attacker to gain elevated privileges on the target system.

The weakness exists due to an error in the implementation of 32 bit syscall interface. A local attacker can gain root privileges.

Mitigation

Install update from vendor's website.

Vulnerable software versions

kernel-rt (Red Hat package): 3.10.0-229.1.2.rt56.141.2.el7_1 - 3.10.0-693.rt56.617.el7

Red Hat Enterprise Linux for Real Time: 7

Red Hat Enterprise Linux for Real Time for NFV: 7

CPE2.3

External links

http://access.redhat.com/errata/RHSA-2018:1355

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.

3) Improper check or handling of exceptional conditions

EUVDB-ID: #VU12520

Risk: Low

CVSSv3.1: 7.7 [CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2018-1087

CWE-ID: CWE-703 - Improper Check or Handling of Exceptional Conditions

Exploit availability: No

Description

The vulnerability allows an adjacent attacker to cause DoS condition or gain elevated privileges on the target system.

The weakness exists in the Linux kernel KVM hypervisor due to improper handling of debug exceptions delivered after a stack switch operation via mov SS or pop SS instructions. During the stack switch operation, the exceptions are deferred. An adjacent attacker can cause the service to crash or gain root privileges.

Mitigation

Install update from vendor's website.

Vulnerable software versions

kernel-rt (Red Hat package): 3.10.0-229.1.2.rt56.141.2.el7_1 - 3.10.0-693.rt56.617.el7

Red Hat Enterprise Linux for Real Time: 7

Red Hat Enterprise Linux for Real Time for NFV: 7

CPE2.3

External links

http://access.redhat.com/errata/RHSA-2018:1355

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.

4) Privilege escalation

EUVDB-ID: #VU12450

Risk: Low

CVSSv3.1: 8.4 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:H/RL:O/RC:C]

CVE-ID: CVE-2018-8897

CWE-ID: CWE-703 - Improper Check or Handling of Exceptional Conditions

Exploit availability: Yes

Description

The vulnerability allows a local attacker to gain elevated privileges on the target system.

The vulnerability exists due to improper implementation of Intel 64 and IA-32 Architectures Software Developer's Manual (SDM) on multiple system kernels, which results in an unexpected behavior for #DB exceptions that are deferred by MOV SS or POP SS. A local user can execute arbitrary code with elevated privileges.

Mitigation

Install update from vendor's website.

Vulnerable software versions

kernel-rt (Red Hat package): 3.10.0-229.1.2.rt56.141.2.el7_1 - 3.10.0-693.rt56.617.el7

Red Hat Enterprise Linux for Real Time: 7

Red Hat Enterprise Linux for Real Time for NFV: 7

CPE2.3

External links

http://access.redhat.com/errata/RHSA-2018:1355

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.

5) Error handling

EUVDB-ID: #VU12337

Risk: Low

CVSSv3.1: 5.7 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2018-1000199

CWE-ID: CWE-388 - Error Handling

Exploit availability: No

Description

The vulnerability allows a local attacker to cause DoS condition on the target system.

The weakness exists in the modify_user_hw_breakpoint() function due to error handling flaw. A local attacker can cause the service to crash.

Mitigation

Install update from vendor's website.

Vulnerable software versions

kernel-rt (Red Hat package): 3.10.0-229.1.2.rt56.141.2.el7_1 - 3.10.0-693.rt56.617.el7

Red Hat Enterprise Linux for Real Time: 7

Red Hat Enterprise Linux for Real Time for NFV: 7

CPE2.3

External links

http://access.redhat.com/errata/RHSA-2018:1355

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.