SB2024011837 - SUSE update for libssh

Description

This security bulletin contains information about 5 secuirty vulnerabilities.

1) Input validation error (CVE-ID: CVE-2023-1667)

The vulnerability allows a remote attacker to bypass implemented security restrictions.

The vulnerability exists due to multiple errors in kex implementation, related to kex guessing algorithm. A remote attacker can bypass implemented security restrictions.

2) Improper Authentication (CVE-ID: CVE-2023-2283)

The vulnerability allows a remote attacker to bypass authentication process.

The vulnerability exists due to an error within the pki_verify_data_signature() function in pki_crypto.c. The pki_key_check_hash_compatible() function can return SSH_OK value if memory allocation error happens later in the function. The  A remote attacker can bypass authentication process and gain unauthorized access to the system.

3) Inadequate encryption strength (CVE-ID: CVE-2023-48795)

The 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.

4) OS Command Injection (CVE-ID: CVE-2023-6004)

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.

5) Unchecked Return Value (CVE-ID: CVE-2023-6918)

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.

Remediation

Install update from vendor's website.

References

• https://www.suse.com/support/update/announcement/2024/suse-su-20240140-1/