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FreeBSD : OpenSSH -- Double-free memory corruption in ssh-agent (76b5068c-8436-11eb-9469-080027f515ea)

high Nessus Plugin ID 147897

Synopsis

The remote FreeBSD host is missing one or more security-related updates.

Description

OpenBSD Project reports :

ssh-agent(1): fixed a double-free memory corruption that was introduced in OpenSSH 8.2 . We treat all such memory faults as potentially exploitable. This bug could be reached by an attacker with access to the agent socket.

On modern operating systems where the OS can provide information about the user identity connected to a socket, OpenSSH ssh-agent and sshd limit agent socket access only to the originating user and root.
Additional mitigation may be afforded by the system's malloc(3)/free(3) implementation, if it detects double-free conditions.

The most likely scenario for exploitation is a user forwarding an agent either to an account shared with a malicious user or to a host with an attacker holding root access.

Solution

Update the affected packages.

See Also

https://www.openssh.com/txt/release-8.5

http://www.nessus.org/u?8d0bca2f

Plugin Details

Severity: High

ID: 147897

File Name: freebsd_pkg_76b5068c843611eb9469080027f515ea.nasl

Version: 1.6

Type: local

Published: 3/19/2021

Updated: 10/18/2021

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5.9

CVSS v2

Risk Factor: Medium

Base Score: 4.6

Temporal Score: 3.4

Vector: CVSS2#AV:N/AC:H/Au:S/C:P/I:P/A:P

CVSS Score Source: CVE-2021-28041

CVSS v3

Risk Factor: High

Base Score: 7.1

Temporal Score: 6.2

Vector: CVSS:3.0/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:freebsd:freebsd:openssh-portable, p-cpe:/a:freebsd:freebsd:openssh-portable-gssapi, p-cpe:/a:freebsd:freebsd:openssh-portable-hpn, cpe:/o:freebsd:freebsd

Required KB Items: Host/local_checks_enabled, Host/FreeBSD/release, Host/FreeBSD/pkg_info

Exploit Ease: No known exploits are available

Patch Publication Date: 3/13/2021

Vulnerability Publication Date: 3/3/2021

Reference Information

CVE: CVE-2021-28041

IAVA: 2021-A-0121-S