FreeBSD : PuTTY -- integer overflow permits memory overwrite by forwarded ssh-agent connections (9b973e97-0a99-11e7-ace7-080027ef73ec)

critical Nessus Plugin ID 97789

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Synopsis

The remote FreeBSD host is missing a security-related update.

Description

Simon G. Tatham reports :

Many versions of PuTTY prior to 0.68 have a heap-corrupting integer overflow bug in the ssh_agent_channel_data function which processes messages sent by remote SSH clients to a forwarded agent connection.
[...]

This bug is only exploitable at all if you have enabled SSH agent forwarding, which is turned off by default. Moreover, an attacker able to exploit this bug would have to have already be able to connect to the Unix-domain socket representing the forwarded agent connection.
Since any attacker with that capability would necessarily already be able to generate signatures with your agent's stored private keys, you should in normal circumstances be defended against this vulnerability by the same precautions you and your operating system were already taking to prevent untrusted people from accessing your SSH agent.

Solution

Update the affected package.

Plugin Details

Severity: Critical

ID: 97789

File Name: freebsd_pkg_9b973e970a9911e7ace7080027ef73ec.nasl

Version: 3.8

Type: local

Family: FreeBSD Local Security Checks

Published: 3/17/2017

Updated: 1/4/2021

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: High

Base Score: 7.5

Temporal Score: 5.9

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

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.8

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

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

Vulnerability Information

CPE: p-cpe:/a:freebsd:freebsd:putty, cpe:/o:freebsd:freebsd

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

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 3/16/2017

Vulnerability Publication Date: 1/29/2017

Reference Information

CVE: CVE-2017-6542

Detections

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