PuTTY < 0.76 Insufficient Verification of Data Authenticity

high Nessus Plugin ID 190360

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Synopsis

The remote Windows host has an SSH client that is affected by an insufficient verification of data authenticity vulnerability.

Description

The remote host has a version of PuTTY installed that is prior to 0.76, which proceeds with establishing an SSH session even if it has never sent a substantive authentication response. This makes it easier for an attacker-controlled SSH server to present a later spoofed authentication prompt (that the attacker can use to capture credential data, and use that data for purposes that are undesired by the client user).
From version 0.76, PuTTY will include an option to abandon an SSH connection if the SSH server ends the user authentication phase of the protocol without requiring any substantive input from PuTTY.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Upgrade to PuTTY version 0.76 or later.

Plugin Details

Severity: High

ID: 190360

File Name: putty_076.nasl

Version: 1.1

Type: local

Agent: windows

Family: Windows

Published: 2/9/2024

Updated: 2/12/2024

Supported Sensors: Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5.2

CVSS v2

Risk Factor: Medium

Base Score: 5.8

Temporal Score: 4.3

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

CVSS Score Source: CVE-2021-36367

CVSS v3

Risk Factor: High

Base Score: 8.1

Temporal Score: 7.1

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

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

Vulnerability Information

CPE: cpe:/a:simon_tatham:putty

Required KB Items: installed_sw/PuTTY, SMB/Registry/Enumerated

Exploit Ease: No known exploits are available

Patch Publication Date: 7/17/2021

Vulnerability Publication Date: 7/9/2021

Reference Information

CVE: CVE-2021-36367

Detections

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