Amazon Linux AMI update for kernel

Published: 2019-03-26 | Updated: 2019-05-22

Risk	Medium
Patch available	YES
Number of vulnerabilities	2
CVE-ID	CVE-2019-9213 CVE-2019-8980
CWE-ID	CWE-476 CWE-401
Exploitation vector	Network
Public exploit	Public exploit code for vulnerability #1 is available. Public exploit code for vulnerability #2 is available.
Vulnerable software Subscribe	Amazon Linux AMI Operating systems & Components / Operating system
Vendor	Amazon Web Services

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) NULL pointer dereference

EUVDB-ID: #VU17910

Risk: Low

CVSSv3.1: 5.1 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:F/RL:O/RC:C]

CVE-ID: CVE-2019-9213

CWE-ID: CWE-476 - NULL Pointer Dereference

Exploit availability: Yes

Description

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

The vulnerability exists due to a NULL pointer dreference error in expand_downwards() in mm/mmap.c that does not check for the mmap minimum address, which makes it easier for attackers to exploit kernel NULL pointer dereferences on non-SMAP platforms. This is related to a capability check for the wrong task. A local user can perform a denial of service (DoS) attack.

Mitigation

Update the affected packages.

i686:
    kernel-debuginfo-common-i686-4.14.106-79.86.amzn1.i686
    kernel-headers-4.14.106-79.86.amzn1.i686
    kernel-tools-debuginfo-4.14.106-79.86.amzn1.i686
    kernel-4.14.106-79.86.amzn1.i686
    perf-4.14.106-79.86.amzn1.i686
    kernel-devel-4.14.106-79.86.amzn1.i686
    kernel-debuginfo-4.14.106-79.86.amzn1.i686
    kernel-tools-devel-4.14.106-79.86.amzn1.i686
    kernel-tools-4.14.106-79.86.amzn1.i686
    perf-debuginfo-4.14.106-79.86.amzn1.i686

src:
    kernel-4.14.106-79.86.amzn1.src

x86_64:
    kernel-debuginfo-4.14.106-79.86.amzn1.x86_64
    kernel-tools-4.14.106-79.86.amzn1.x86_64
    kernel-debuginfo-common-x86_64-4.14.106-79.86.amzn1.x86_64
    perf-4.14.106-79.86.amzn1.x86_64
    kernel-headers-4.14.106-79.86.amzn1.x86_64
    kernel-tools-debuginfo-4.14.106-79.86.amzn1.x86_64
    kernel-tools-devel-4.14.106-79.86.amzn1.x86_64
    perf-debuginfo-4.14.106-79.86.amzn1.x86_64
    kernel-4.14.106-79.86.amzn1.x86_64
    kernel-devel-4.14.106-79.86.amzn1.x86_64

Vulnerable software versions

Amazon Linux AMI: All versions

External links

http://alas.aws.amazon.com/ALAS-2019-1179.html

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, a fully functional exploit for this vulnerability is available.

2) Memory leak

EUVDB-ID: #VU17831

Risk: Medium

CVSSv3.1: 6.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:P/RL:O/RC:C]

CVE-ID: CVE-2019-8980

CWE-ID: CWE-401 - Missing release of memory after effective lifetime

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to improper memory operations in the kernel_read_file function, as defined in the fs/exec.c source code file. A remote attacker can send malicious file that triggers vfs_read failures and memory leak condition and perform a denial of service attack.

Mitigation

Update the affected packages.

i686:
    kernel-debuginfo-common-i686-4.14.106-79.86.amzn1.i686
    kernel-headers-4.14.106-79.86.amzn1.i686
    kernel-tools-debuginfo-4.14.106-79.86.amzn1.i686
    kernel-4.14.106-79.86.amzn1.i686
    perf-4.14.106-79.86.amzn1.i686
    kernel-devel-4.14.106-79.86.amzn1.i686
    kernel-debuginfo-4.14.106-79.86.amzn1.i686
    kernel-tools-devel-4.14.106-79.86.amzn1.i686
    kernel-tools-4.14.106-79.86.amzn1.i686
    perf-debuginfo-4.14.106-79.86.amzn1.i686

src:
    kernel-4.14.106-79.86.amzn1.src

x86_64:
    kernel-debuginfo-4.14.106-79.86.amzn1.x86_64
    kernel-tools-4.14.106-79.86.amzn1.x86_64
    kernel-debuginfo-common-x86_64-4.14.106-79.86.amzn1.x86_64
    perf-4.14.106-79.86.amzn1.x86_64
    kernel-headers-4.14.106-79.86.amzn1.x86_64
    kernel-tools-debuginfo-4.14.106-79.86.amzn1.x86_64
    kernel-tools-devel-4.14.106-79.86.amzn1.x86_64
    perf-debuginfo-4.14.106-79.86.amzn1.x86_64
    kernel-4.14.106-79.86.amzn1.x86_64
    kernel-devel-4.14.106-79.86.amzn1.x86_64

Vulnerable software versions

Amazon Linux AMI: All versions

External links

http://alas.aws.amazon.com/ALAS-2019-1179.html

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

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.