Ubuntu update for openssh

1) Double Free

EUVDB-ID: #VU51444

Risk: Medium

CVSSv4.0: 4.4 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2021-28041

CWE-ID: CWE-415 - Double Free

Exploit availability: No

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error in ssh-agent. A remote attacker can trick the victim to connect to a server, where the attacker has root privileges, pass specially crafted data to the ssh client, trigger a double free error and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation

Update the affected package openssh to the latest version.

Vulnerable software versions

Ubuntu: 20.04 - 20.10

openssh-client (Ubuntu package): before 1:8.2p1-4ubuntu0.2

CPE2.3

• cpe:2.3:o:canonical:ubuntu:20.04:*:*:*:*:*:*:*
• cpe:2.3:o:canonical:ubuntu:20.10:*:*:*:*:*:*:*
• cpe:2.3:a:canonical:openssh-client_ubuntu_package:*:*:*:*:*:ubuntu:*:*

External links

https://ubuntu.com/security/notices/USN-4762-1

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.