SB2025031248 - Fedora EPEL 10.0 update for libssh2
Published: March 12, 2025
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 2 secuirty vulnerabilities.
1) 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.
2) 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.