CVE-2013-0248 Apache Commons FileUpload - Insecure examples 
Severity: Low 
Vendor: The Apache Software Foundation 
Versions Affected: 
- Commons FileUpload 1.0 to 1.2.2 
Description: 
Commons FileUpload provides file upload capability for Servlets and web 
applications. During the upload process, FileUpload may (depending on 
configuration) save the uploaded file temporarily on disk. By default 
this will be in the system wide tmp directory. Because the temporary 
files have predictable file names and are stored in a publicly writeable 
location they are vulnerable to a TOCTOU attack. 
A successful attack requires that the attacker has write access to the 
tmp directory. The attack can be prevented by setting the repository to 
a non-publicly writeable location. 
The documentation for FileUpload does not highlight the potential 
security implications of not setting a repository, nor do the provided 
examples set a repository. This may have caused users to use FileUpload 
in an insecure manner. 
Mitigation: 
Setting the repository to a non-publicly writeable location such as that 
defined by the ServletContext attribute javax.servlet.context.tempdir 
will prevent the TOCTOU attack. 

Credit: 
This issue was identified by Karl Dyszynski and Hugo Vazquez Carames of 
SonicWall