SB2025022562 - Ubuntu update for proftpd-dfsg

Description

This security bulletin contains information about 3 secuirty vulnerabilities.

1) 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.

2) Out-of-bounds read (CVE-ID: CVE-2023-51713)

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

The vulnerability exists due to a boundary condition within the make_ftp_cmd() function in main.c. A remote user can pass a specially crafted command to the server, trigger an out-of-bounds read error and perform a denial of service (DoS) attack.

3) Improper privilege management (CVE-ID: CVE-2024-48651)

The vulnerability allows a remote user to compromise the affected system.

The vulnerability exists due to improper privilege management when handling users without assigned supplementary groups. If the user has no groups assigned to their account, the server will assume the GID of 0 for this account. As a result, the user will gain access to files and directories owned by the system root user and will be able to modify them at will, leading to privilege escalation and system compromise.

Remediation

Install update from vendor's website.

References

• https://ubuntu.com/security/notices/USN-7297-1