by Tan Chew Keong
Release Date: 2008-06-27
[en] [jp]
Summary
A vulnerability has been found within the FTP client in AceFTP. When exploited, this vulnerability allows an anonymous attacker to write files to arbitrary locations on a Windows user's system.
Tested Versions
Details
This advisory discloses a vulnerability within the FTP client in AceFTP. When exploited, this vulnerability allows an anonymous attacker to write files to arbitrary locations on a Windows user's system.
The FTP client does not properly sanitise filenames containing directory traversal sequences (forward-slash) that are received from an FTP server in response to the LIST command.
An example of such a response from a malicious FTP server is shown below.
Response to LIST (forward-slash):
-rw-r--r-- 1 ftp ftp 20 Mar 01 05:37 /../../../../../../../../../testfile.txt\r\n
By tricking a user to download a directory from a malicious FTP server that contains files with fowward-slash directory traversal sequences in their filenames, it is possible for the attacker to write files to arbitrary locations on a user's system with privileges of that user. An attacker can potentially leverage this issue to write files into a user's Windows Startup folder and execute arbitrary code when the user logs on.
POC / Test Code
Please download the POC here and follow the instructions below.
Joseph: King Of Dreams (2000) -
Released on November 7, 2000, is an animated biblical musical drama from DreamWorks Animation . It serves as a direct-to-video prequel and companion piece to the 1998 theatrical hit The Prince of Egypt . Plot and Themes
The film adapts the Book of Genesis (chapters 37–50), centering on Joseph, the "miracle child" born to Jacob and Rachel. Joseph: King of Dreams (Video 2000) - IMDb Joseph: King of Dreams (2000)
Patch / Workaround
Avoid downloading files/directories from untrusted FTP servers.
Disclosure Timeline
2008-06-15 - Vulnerability Discovered.
2008-06-16 - Vulnerability Details Sent to Vendor via online support form (no reply).
2008-06-18 - Vulnerability Details Sent to Vendor again via online support form (no reply).
2008-06-25 - Vulnerability Details Sent to Vendor again via online support form (no reply).
2008-06-27 - Public Release.