Software Engineering Institute

ProCheckup has reported a vulnerability in iPlanet Web Server, Enterprise Edition and Netscape Enterprise Server running on Windows NT based operating systems. The iPlanet and NES servers provide a feature called Web Publisher. According to NES documentation:

Netscape Enterprise Server 4.0 clients can use Web Publisher to collaborate on projects by directly accessing, editing, and managing file on remote servers. Web Publisher provides sophisticated features for server clients, such as file management, editing and publishing, and access control.
If Web Publishing is enabled, a malformed ?wp-html-rend command can crash the web server process. To determine if Web Publisher is enabled, enter the following URL:

http://<name of server>/publisher
If Web Publisher is enabled, a page should appear. Note that this vulnerability does not affect Unix systems.

An unauthenticated remote attacker can cause a denial-of-service condition by sending malformed ?wp-html-rend commands to a vulnerable server.

Disable Web Publishing
iPlanet recommends disabling Web Publisher and Directory Indexing on external servers:

http://developer.netscape.com/docs/manuals/enterprise/40/ag/esapuirf.htm#1005372

Another method for disabling Web Publisher is to use a Netscape Server Application Programming Interface (NSAPI) Server Application Function (SAF):

http://knowledgebase.iplanet.com/ikb/kb/articles/7761.html

Filter HTTP TrafficIt may be possible to use an application layer filter to detect and block HTTP requests containing the ?wp-html-rend command.