ALFTP FTP Client 'LIST' Command Directory Traversal Vulnerability

Bugtraq ID:	29585
Class:	Input Validation Error
CVE:	CVE-2008-2702
Remote:	Yes
Local:	No
Published:	Jun 06 2008 12:00AM
Updated:	May 07 2015 05:28PM
Credit:	Tan Chew Keong
Vulnerable:	ESTsoft ALFTP 5.0 (Korean) ESTsoft ALFTP 4.1 beta 2 (English)
Not Vulnerable:	ESTsoft ALFTP 5.1 beta 1

ALFTP FTP Client 'LIST' Command Directory Traversal Vulnerability

ALFTP is prone to a directory-traversal vulnerability because the application fails to sufficiently sanitize user-supplied input. This issue occurs in the FTP client.

Exploiting this issue will allow an attacker to write arbitrary files to locations outside of the application's current directory. This could help the attacker launch further attacks.

ALFTP 4.1 beta 2 (English) and 5.0 (Korean) are vulnerable; other versions may also be affected.

ALFTP FTP Client 'LIST' Command Directory Traversal Vulnerability

An attacker can exploit this issue by enticing an unsuspecting victim to connect to a malicious server.

The following proofs of concepts are available:

Response to LIST (backslash):

\..\..\..\..\..\..\..\..\..\testfile.txt\r\n

Response to LIST (forward-slash):
/../../../../../../../../../testfile.txt\r\n

ALFTP FTP Client 'LIST' Command Directory Traversal Vulnerability

Solution:
Updates are available. Please contact the vendor for more information.

ALFTP FTP Client 'LIST' Command Directory Traversal Vulnerability

References:

• ALFTP Homepage (ESTsoft)
  
• ESTsoft ALFTP FTP Client Directory Traversal Vulnerability (vuln.sg)