Ubuntu update for libssh



Risk Medium
Patch available YES
Number of vulnerabilities 2
CVE-ID CVE-2023-6004
CVE-2023-6918
CWE-ID CWE-78
CWE-252
Exploitation vector Network
Public exploit N/A
Vulnerable software
 Ubuntu
Operating systems & Components / Operating system

libssh-gcrypt-4 (Ubuntu package)
Operating systems & Components / Operating system package or component

libssh-4 (Ubuntu package)
Operating systems & Components / Operating system package or component

Vendor Canonical Ltd.

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) OS Command Injection

EUVDB-ID: #VU84538

Risk: Medium

CVSSv4.0: 4.8 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2023-6004

CWE-ID: CWE-78 - Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

Exploit availability: No

Description

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

The vulnerability exists due to improper input validation in OpenSSH client. If an invalid user or hostname that contained shell metacharacters was passed to ssh(1), and a ProxyCommand, LocalCommand directive or "match exec" predicate referenced the user or hostname via %u, %h or similar expansion token, then an attacker who could supply arbitrary user/hostnames to ssh(1) could potentially perform command injection depending on what quoting was present in the user-supplied ssh_config(5) directive.


Mitigation

Update the affected package libssh to the latest version.

Vulnerable software versions

Ubuntu: 16.04 - 18.04

libssh-gcrypt-4 (Ubuntu package): before Ubuntu Pro

libssh-4 (Ubuntu package): before Ubuntu Pro

CPE2.3 External links

https://ubuntu.com/security/notices/USN-6592-2


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) Unchecked Return Value

EUVDB-ID: #VU84540

Risk: Low

CVSSv4.0: 1.7 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2023-6918

CWE-ID: CWE-252 - Unchecked Return Value

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to libssh does not check for returned values of message digest (MD) operations in low memory conditions. A remote attacker can terminate the connection or force the library to use weak keys.

Mitigation

Update the affected package libssh to the latest version.

Vulnerable software versions

Ubuntu: 16.04 - 18.04

libssh-gcrypt-4 (Ubuntu package): before Ubuntu Pro

libssh-4 (Ubuntu package): before Ubuntu Pro

CPE2.3 External links

https://ubuntu.com/security/notices/USN-6592-2


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.



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