Brian Andle created WW-5184:
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Summary: Add optional parameter value check to
ParametersInterceptor
Key: WW-5184
URL: https://issues.apache.org/jira/browse/WW-5184
Project: Struts 2
Issue Type: Improvement
Reporter: Brian Andle
It is known that developers utilizing Struts/Freemarker should always ensure
proper sanitization to prevent OGNL/Freemarker evaluation on untrusted user
input when %{/$\{ in FTL being passed into Struts tags.
The following would end up rendering 81
Payload:
{code:java}
untrustedInput=%25%7B9%2A9%7D {code}
FTL:
{code:java}
<@s.form theme="simple" action="${untrustedInput}" id="myForm4">
</@s.form> {code}
Java:
{code:java}
private String untrustedInput;
public String getUntrustedInput() {
return untrustedInput;
}
public void setUntrustedInput(String untrustedInput) {
this.untrustedInput = untrustedInput;
} {code}
These patterns aren't always practical to resolve/find especially in legacy
code. This isn't a solely a legacy code of course it's just as easy to make a
mistake in newer code as well.
This ticket is to add an optional `params.excludeValuePatterns` so that
ParametersInterceptor can drop incoming parameter itself if the value patterns
are excluded.
{code:java}
.*\$\{.*?\}.*,.*%\{.*?\}.* {code}
Since this is a pattern and would be executed against the values themselves
there is the potential of a performance impact however I since it's optional we
shouldn't see any measurable impact when not enabled.
*NOTE:* I did add a `params.acceptValuePatterns` pattern that is null/disabled
by default. This might not ever be used but mimic'd the Pattern matcher the
ParametersInterceptor/CookieInterceptor.
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