Amazon Linux AMI update for openssh

1) Denial of service

EUVDB-ID: #VU9333

Risk: Low

CVSSv4.0: 4.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2017-15906

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

Exploit availability: No

Description

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

The weakness exists in the process_open() function due to improper prevention of write operations in read-only mode. A remote attacker can create zero-length files and cause the service to crash.

Successful exploitation of the vulnerability results in denial of service.

Mitigation

Update the affected packages.

i686:
    openssh-7.4p1-16.69.amzn1.i686
    openssh-keycat-7.4p1-16.69.amzn1.i686
    openssh-cavs-7.4p1-16.69.amzn1.i686
    pam_ssh_agent_auth-0.10.3-2.16.69.amzn1.i686
    openssh-ldap-7.4p1-16.69.amzn1.i686
    openssh-clients-7.4p1-16.69.amzn1.i686
    openssh-debuginfo-7.4p1-16.69.amzn1.i686
    openssh-server-7.4p1-16.69.amzn1.i686

src:
    openssh-7.4p1-16.69.amzn1.src

x86_64:
    openssh-cavs-7.4p1-16.69.amzn1.x86_64
    openssh-7.4p1-16.69.amzn1.x86_64
    pam_ssh_agent_auth-0.10.3-2.16.69.amzn1.x86_64
    openssh-keycat-7.4p1-16.69.amzn1.x86_64
    openssh-ldap-7.4p1-16.69.amzn1.x86_64
    openssh-clients-7.4p1-16.69.amzn1.x86_64
    openssh-debuginfo-7.4p1-16.69.amzn1.x86_64
    openssh-server-7.4p1-16.69.amzn1.x86_64

Vulnerable software versions

Amazon Linux AMI: All versions

CPE2.3

• cpe:2.3:o:amazon_web_services:amazon_linux_ami:*:*:*:*:*:*:*:*

External links

https://alas.aws.amazon.com/ALAS-2018-1018.html

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.