Ubuntu update for openssh
| Risk | Low |
| Patch available | YES |
| Number of vulnerabilities | 2 |
| CVE-ID | CVE-2023-48795 CVE-2023-28531 |
| CWE-ID | CWE-326 CWE-255 |
| Exploitation vector | Network |
| Public exploit | Public exploit code for vulnerability #1 is available. |
| Vulnerable software |
Ubuntu Operating systems & Components / Operating system openssh-server (Ubuntu package) Operating systems & Components / Operating system package or component openssh-client (Ubuntu package) Operating systems & Components / Operating system package or component |
| Vendor | Canonical Ltd. |
Security Bulletin
This security bulletin contains information about 2 vulnerabilities.
1) Inadequate encryption strength
EUVDB-ID: #VU84537
Risk: Low
CVSSv4.0: 2.9 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P/U:Clear]
CVE-ID: CVE-2023-48795
CWE-ID:
CWE-326 - Inadequate Encryption Strength
Exploit availability: Yes
DescriptionThe vulnerability allows a remote attacker to perform MitM attack.
The vulnerability exists due to incorrect implementation of the SSH Binary Packet Protocol (BPP), which mishandles the handshake phase and the use of sequence numbers. A remote attacker can perform MitM attack and delete the SSH2_MSG_EXT_INFO message sent before authentication starts, allowing the attacker to disable a subset of the keystroke timing obfuscation features introduced in OpenSSH 9.5.
The vulnerability was dubbed "Terrapin attack" and it affects both client and server implementations.
Update the affected package openssh to the latest version.
Vulnerable software versionsUbuntu: 20.04 - 23.10
openssh-server (Ubuntu package): before 1:8.2p1-4ubuntu0.10
openssh-client (Ubuntu package): before 1:8.2p1-4ubuntu0.10
CPE2.3- cpe:2.3:o:canonical:ubuntu:20.04:*:*:*:*:*:*:*
- cpe:2.3:o:canonical:ubuntu:22.04:*:*:*:*:*:*:*
- cpe:2.3:o:canonical:ubuntu:23.04:*:*:*:*:*:*:*
- cpe:2.3:o:canonical:ubuntu:23.10:*:*:*:*:*:*:*
- cpe:2.3:o:canonical:openssh-server_ubuntu_package:*:*:*:*:*:ubuntu:*:*
- cpe:2.3:o:canonical:openssh-client_ubuntu_package:*:*:*:*:*:ubuntu:*:*
https://ubuntu.com/security/notices/USN-6560-1
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.
2) Credentials management
EUVDB-ID: #VU73775
Risk: Low
CVSSv4.0: 1.7 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]
CVE-ID: CVE-2023-28531
CWE-ID:
CWE-255 - Credentials Management
Exploit availability: No
DescriptionThe vulnerability allows a remote user to bypass implemented security restrictions.
the vulnerability exists due to a logic error in ssh-add when adding smartcard keys to ssh-agent with the per-hop destination constraints. As a result, the keys are added without constraints.
Update the affected package openssh to the latest version.
Vulnerable software versionsUbuntu: 20.04 - 23.10
openssh-server (Ubuntu package): before 1:8.2p1-4ubuntu0.10
openssh-client (Ubuntu package): before 1:8.2p1-4ubuntu0.10
CPE2.3- cpe:2.3:o:canonical:openssh-server_ubuntu_package:*:*:*:*:*:ubuntu:*:*
- cpe:2.3:o:canonical:openssh-client_ubuntu_package:*:*:*:*:*:ubuntu:*:*
https://ubuntu.com/security/notices/USN-6560-1
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.
