Ubuntu update for openssh
| Risk | Medium |
| Patch available | YES |
| Number of vulnerabilities | 2 |
| CVE-ID | CVE-2023-48795 CVE-2023-51385 |
| CWE-ID | CWE-326 CWE-78 |
| Exploitation vector | Network |
| Public exploit | Public exploit code for vulnerability #2 is available. |
| Vulnerable software Subscribe |
Ubuntu Operating systems & Components / Operating system openssh-client (Ubuntu package) Operating systems & Components / Operating system package or component openssh-server (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
CVSSv3.1: 3.2 [CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N/E:U/RL:O/RC:C]
CVE-ID: CVE-2023-48795
CWE-ID:
CWE-326 - Inadequate Encryption Strength
Exploit availability: No
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: 16.04 - 18.04
openssh-client (Ubuntu package): before Ubuntu Pro
openssh-server (Ubuntu package): before Ubuntu Pro (Infra-only)
CPE2.3 External linkshttp://ubuntu.com/security/notices/USN-6560-2
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.
2) OS Command Injection
EUVDB-ID: #VU84789
Risk: Medium
CVSSv3.1: 6.7 [CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C]
CVE-ID: CVE-2023-51385
CWE-ID:
CWE-78 - Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
Exploit availability: Yes
DescriptionThe vulnerability allows a remote attacker to execute arbitrary shell commands on the target system.
The vulnerability exists due to improper input validation when processing user names, if a user name or host name has shell metacharacters, and this name is referenced by an expansion token in certain situations. A remote attacker can execute arbitrary OS commands via an untrusted Git repository.
MitigationUpdate the affected package openssh to the latest version.
Vulnerable software versionsUbuntu: 16.04 - 18.04
openssh-client (Ubuntu package): before Ubuntu Pro
openssh-server (Ubuntu package): before Ubuntu Pro (Infra-only)
CPE2.3 External linkshttp://ubuntu.com/security/notices/USN-6560-2
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.
