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Rapid7 Advisory R7-0028: Caucho Resin World Readable DOS Device


May 14, 2007 - The Caucho Resin web application server does not properly sanitize get requests on windows servers. By specifying a DOS device file name appended with an arbitrary extension, an attacker could read a continuous stream of data from any COM or LPT device on the system.

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Affected system(s):


  • Caucho Resin Professional v3.1.0 for Windows
  • Caucho Resin v3.1.0 for Windows
  • Caucho Resin v3.0.21 for Windows
  • Caucho Resin v3.0.20 for Windows
  • Caucho Resin v3.0.19 for Windows
  • Caucho Resin v3.0.18 for Windows
  • Caucho Resin v3.0.17 for Windows


  • Caucho Resin v3.1.1 for Windows
  • Caucho Resin Professional v3.1.1 for Windows

Vendor Info

Caucho Technology, Inc.

Caucho was notified of this vulnerability on May 3rd, 2007.They fixed this vulnerability in the latest unofficial snapshot of Resin 3.1.1, available from Caucho's Web site.


Upgrade to Caucho Resin 3.1.1 or later.

Detailed Analysis

Caucho Resin is a servlet and JSP server. Resin ships with its own stand-alone web server which runs by default on port 8080. Any remote user can request URLs of the form:


(where "[device]" can be COM1, COM2, LPT1, etc.) to open an input stream to any hardware serial or LPT device on the system.

Once the initial connection is made, Resin will hold a lock on the device and subsequent requests to the same device may result in a 404/Not Found response from the server.

Discovered by Derek Abdine of Rapid7.

Disclaimer & Copyright

Rapid7, LLC is not responsible for the misuse of the information provided in our security advisories. These advisories are a service to the professional security community. There are NO WARRANTIES with regard to this information. Any application or distribution of this information constitutes acceptance AS IS, at the user's own risk. This information is subject to change without notice.

This advisory Copyright (C) 2007 Rapid7, LLC. Permission is hereby granted to redistribute this advisory, providing that no changes are made and that the copyright notices and disclaimers remain intact.