Ubuntu update for OpenSSH

1) Security restrictions bypass

EUVDB-ID: #VU16988

Risk: Low

CVSSv4.0: 6.9 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P/U:Clear]

CVE-ID: CVE-2019-6111

CWE-ID: CWE-20 - Improper input validation

Exploit availability: Yes

Description

The vulnerability allows a remote attacker to bypass security restrictions on the target system.

The weakness exists due to missing received object name validation by the scp client. A malicious SCP server can overwrite arbitrary files in the SCP client target directory. If a recursive operation (-r) is performed, the server can manipulate subdirectories as well (for example overwrite .ssh/authorized_keys).

Mitigation

Update the affected packages.

Ubuntu 18.10

openssh-client - 1:7.7p1-4ubuntu0.3

Ubuntu 18.04 LTS

openssh-client - 1:7.6p1-4ubuntu0.3

Ubuntu 16.04 LTS

openssh-client - 1:7.2p2-4ubuntu2.8

Ubuntu 14.04 LTS

openssh-client - 1:6.6p1-2ubuntu2.13

Vulnerable software versions

openssh (Ubuntu package): 1:6.6p1-2ubuntu2.2 - 1:7.7p1-4ubuntu0.2

CPE2.3

• cpe:2.3:o:canonical:openssh_ubuntu_package:1:6.6p1-2ubuntu2.2:*:*:*:*:ubuntu:*:*
• cpe:2.3:o:canonical:openssh_ubuntu_package:1:6.6p1-2ubuntu2.3:*:*:*:*:ubuntu:*:*
• cpe:2.3:o:canonical:openssh_ubuntu_package:1:6.6p1-2ubuntu2.4:*:*:*:*:ubuntu:*:*

External links

https://usn.ubuntu.com/3885-2/

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.