ColoradoFTP 1.3 Prime Edition (Build 8) Directory Traversal

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01. ### Advisory Information ###  
  
Title: Directory Traversal Vulnerability in ColoradoFTP v1.3 Prime   
Edition (Build 8)  
Date published: n/a  
Date of last update: n/a  
Vendors contacted: ColoradoFTP author Sergei Abramov  
Discovered by: Rv3Laboratory [Research Team]  
Severity: High  
  
  
02. ### Vulnerability Information ###  
  
OVE-ID: OVE-20160718-0006  
CVSS v2 Base Score: 8.5  
CVSS v2 Vector: (AV:N/AC:M/Au:S/C:C/I:C/A:C)  
Component/s: ColoradoFTP Core v1.3  
Class: Path Traversal  
  
  
03. ### Introduction ###  
  
ColoradoFTP is the open source Java FTP server. It is fast, reliable and   
extendable.  
Fully compatible with RFC 959 and RFC 3659 (File Transfer Protocol and   
Extensions)  
this implementation makes it easy to extend the functionality with   
virtually any feature.  
Well commented source code and existing plug-ins make it possible to   
shape the  
FTP server just the way you want!  
  
http://cftp.coldcore.com/  
  
04. ### Vulnerability Description ###  
  
The default installation and configuration of Colorado FTP Prime Edition   
(Build 8) is prone to a  
security vulnerability. Colorado FTP contains a flaw that may allow a   
remote attacker to traverse directories on the FTP server.  
A remote attacker (a colorado FTP user) can send a command (MKDIR, PUT,   
GET or DEL) followed by sequences (\\\..\\) to traverse directories  
and create, upload, download or delete the contents of arbitrary files   
and directories on the FTP server.  
To exploit the vulnerability It is important to use "\\\" at the   
beginning of string.  
  
  
05. ### Technical Description / Proof of Concept Code ###  
  
By supplying "\\\..\\..\\..\\..\\" in the file path, it is possible to   
trigger a directory traversal flaw, allowing the attacker  
(anonymous user or Colorado FTP user) to upload or download a file   
outside the virtual directory.  
  
  
05.01  
We tried to upload a file (netcat - nc.exe), to Windows %systemroot%   
directory (C:\WINDOWS\system32\) using a PUT command:  
  
ftp> put nc.exe \\\..\\..\\..\\Windows\\system32\\nc.exe  
  
Netcat was successfully uploaded.  
  
  
05.02  
We tried to create a directory (test), using a MKDIR command:  
  
ftp> mkdir nc.exe \\\..\\..\\..\\test  
  
The directory test was successfully created.  
  
  
06. ### Business Impact ###  
  
This may allow an attacker to upload and download files from remote machine.  
  
  
07. ### Systems Affected ###  
  
This vulnerability was tested against: ColoradoFTP v1.3 Prime Edition   
(Build 8)  
O.S.: Microsoft Windows 7 32bit  
JDK: v1.7.0_79  
Others versions are probably affected too, but they were not checked.  
  
  
08. ### Vendor Information, Solutions and Workarounds ###  
  
This issue is fixed in ColoradoFTP Prime Edition (Build 9),  
which can be downloaded from:  
  
http://cftp.coldcore.com/download.htm  
  
  
09. ### Credits ###  
  
Rv3Laboratory [Research Team] - www.Rv3Lab.org  
  
This vulnerability has been discovered by:  
Rv3Lab - [www.rv3lab.org] - research(at)rv3lab(dot)org  
Christian Catalano aka wastasy - wastasy(at)rv3lab(dot)org  
Marco Fornaro aka Chaplin89 - chaplin89(at)rv3lab(dot)org  
  
  
10. ### Vulnerability History ###  
  
July 07th, 2016: Vulnerability discovered.  
July 19th, 2016: Vendor informed. [Colorado FTP team]  
July 21st, 2016: Vendor responds asking for details.  
July 28th, 2016: Sent detailed information to the vendor.  
August 08th, 2016: Vendor confirms vulnerability.  
August 10th, 2016: Vendor reveals patch release date.  
August 11th, 2016: Vulnerability disclosure  
  
  
11. ### Disclaimer ###  
  
The information contained within this advisory is supplied "as-is" with  
no warranties or guarantees of fitness of use or otherwise.  
We accept no responsibility for any damage caused by the use or misuse of  
this information.  
  
  
12. ### About Rv3Lab ###  
  
Rv3Lab is an independent Security Research Lab.  
For more information, please visit [www.Rv3Lab.org]  
For more information regarding the vulnerability feel free to contact the  
Rv3Research Team: research(at)rv3lab(dot)org  
  
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