SB2024012906 - Red Hat Enterprise Linux 8.6 Extended Update Support update for libssh
Published: January 29, 2024 Updated: January 31, 2025
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 3 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.
Remediation
Install update from vendor's website.