I'm trying to find a vulnerability in a search CGI for a customer. Basically, the code inputs form data into a reg exp without checking for "bad" characters. Without knowing the code, is there anyway to run commands on this webserver (NT) through this reg exp?

Here's an example; when I type in: (?{eval"dir";}) The webserver returns the following:

CGI Error
The specified CGI application misbehaved by not returning a complete set of HTTP headers. The headers it did return are:

/(?{eval"dir";})/: Eval-group not allowed at runtime, use re 'eval' at D:\Inetpub\cgibin\search.pl line 61.

But there is one gotcha... any time I enter a space, the expression is ended. For example, if the string above would have contained eval "dir"; instead of eval"dir"; then the output would have been:
/(?{eval/: Sequence (?{...}) not terminated or not {}-balanced

Any ideas?

In reply to regular expression vulnerable? by slash-d

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