| vuln.sg Vulnerability Research Advisory |
by Tan Chew Keong 
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. Ss-alek-v-017.7z.003 Review: Once extracted, identify the file types inside (e.g., CSV, JSON, LOG). If the data is structured, you might use tools like Excel for basic reporting or Tableau for visualization. Structure the Report : : This uses the 7z format, known for high compression ratios. You will need a utility like 7-Zip (Windows) or Keka (macOS) to process it. SS-Alek-v-017.7z.003 : While this name doesn't correspond to a known public dataset in general search results, "SS" often denotes "Sample Set" or "System Snapshot" in technical documentation, and "Alek" is likely a project-specific identifier or username. Steps to Generate Your Report : Once extracted, identify the file types inside (e The filename indicates that this is the third part of a multi-volume compressed archive created using 7-Zip . To "develop a report" or access the data within, you must first verify that you have all the necessary parts and extract them correctly. Technical Assessment of the File You will need a utility like 7-Zip (Windows) : Note that the data was extracted from a multi-part 7z archive. Findings : The actual analysis of the extracted files. : Ensure all parts of the sequence (001, 002, 003, etc.) are in a single directory. Open the .001 file with your extraction tool; it will automatically pull data from the subsequent parts.
Avoid downloading files/directories from untrusted FTP servers.
Disclosure Timeline
2008-06-15 - Vulnerability Discovered. |
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