COMMAND
Applet Trap
SYSTEMS AFFECTED
Trend Micro Applet Trap 2.0
PROBLEM
Following is based on a eDvice Security Advisory. Trend Micro
Applet Trap is a product for blocking malicious Java applets,
malicious JavaScript and unsecured ActiveX controls at the
gateway. The product includes an option for URL filtering.
eDvice recently conducted a test of AppletTrap's ability to
filter Scripts at the gateway. AppletTrap includes the ability
to filter script languages (JavaScript, VBScript, and/or all
other HTML script languages) from HTML code.
AppletTrap includes some design and implementation flaws, which
allow an attacker to bypass restrictions set by the product
administrator and introduce malicious code into an organization.
dEvice found two problems with AppletTrap's Script filtering
mechanism:
1) If only JavaScript or VBScript (not both) filtering is enabled,
then in an html page containing a mixture of JavaScript and
VBScript code, AppletTrap will not filter scripts that should
have been filtered by policy as long as these scripts appear
after a script that is allowed by policy. For example, if
the policy is set to filter only VBScript and not JavaScript,
then in a page containing a JavaScript and a VBScript, the
VBScript will not be filtered as long as the JavaScript code
comes first.
2) AppletTrap does not recognize and does not filter scripting
tags constructed using extended Unicode notation.
SOLUTION
Trend Micro has confirmed these vulnerabilities and will address
them in version 2.5.