Ubuntu update for Linux kernel



Published: 2017-12-07
Risk Low
Patch available YES
Number of vulnerabilities 3
CVE-ID CVE-2017-16939
CVE-2017-1000405
CVE-2017-12146
CWE-ID CWE-416
CWE-362
Exploitation vector Local
Public exploit Public exploit code for vulnerability #1 is available.
Public exploit code for vulnerability #2 is available.
Vulnerable software
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Ubuntu
Operating systems & Components / Operating system

Vendor Canonical Ltd.

Security Bulletin

This security bulletin contains information about 3 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

Update the affected packages

Ubuntu 17.04:
linux-image-4.10.0-42-generic-lpae 4.10.0-42.46
linux-image-generic-lpae 4.10.0.42.42
linux-image-4.10.0-42-generic 4.10.0-42.46
linux-image-4.10.0-1023-raspi2 4.10.0-1023.26
linux-image-generic 4.10.0.42.42
linux-image-4.10.0-42-lowlatency 4.10.0-42.46
linux-image-lowlatency 4.10.0.42.42
linux-image-raspi2 4.10.0.1023.24

Vulnerable software versions

Ubuntu: 17.04

External links

http://www.ubuntu.com/usn/usn-3508-1/


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) Race condition

EUVDB-ID: #VU9520

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-2017-1000405

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

Update the affected packages

Ubuntu 17.04:
linux-image-4.10.0-42-generic-lpae 4.10.0-42.46
linux-image-generic-lpae 4.10.0.42.42
linux-image-4.10.0-42-generic 4.10.0-42.46
linux-image-4.10.0-1023-raspi2 4.10.0-1023.26
linux-image-generic 4.10.0.42.42
linux-image-4.10.0-42-lowlatency 4.10.0-42.46
linux-image-lowlatency 4.10.0.42.42
linux-image-raspi2 4.10.0.1023.24

Vulnerable software versions

Ubuntu: 17.04

External links

http://www.ubuntu.com/usn/usn-3508-1/


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.

3) Race condition

EUVDB-ID: #VU9606

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-2017-12146

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

Exploit availability: No

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a race condition between a read operation and a store operation that involve different overrides in driver_override implementation in drivers/base/platform.c. A local user can execute arbitrary code on the target system with elevated privileges.

Mitigation

Update the affected packages

Ubuntu 17.04:
linux-image-4.10.0-42-generic-lpae 4.10.0-42.46
linux-image-generic-lpae 4.10.0.42.42
linux-image-4.10.0-42-generic 4.10.0-42.46
linux-image-4.10.0-1023-raspi2 4.10.0-1023.26
linux-image-generic 4.10.0.42.42
linux-image-4.10.0-42-lowlatency 4.10.0-42.46
linux-image-lowlatency 4.10.0.42.42
linux-image-raspi2 4.10.0.1023.24

Vulnerable software versions

Ubuntu: 17.04

External links

http://www.ubuntu.com/usn/usn-3508-1/


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.



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