Skipfish is an active web application security reconnaissance tool. It prepares an interactive sitemap for the targeted site by carrying out a recursive crawl and dictionary-based probes. The resulting map is then annotated with the output from a number of active (but hopefully non-disruptive) security checks. The final report generated by the tool is meant to serve as a foundation for professional web application security assessments.
Keep in mind that all types of security testing can be disruptive. Although the skipfish scanner is designed not to carry out malicious attacks, it may accidentally interfere with the operations of the site. You must accept the risk, and plan accordingly. Run the scanner against test instances where feasible, and be prepared to deal with the consequences if things go wrong.
Continue Reading... Keep in mind that all types of security testing can be disruptive. Although the skipfish scanner is designed not to carry out malicious attacks, it may accidentally interfere with the operations of the site. You must accept the risk, and plan accordingly. Run the scanner against test instances where feasible, and be prepared to deal with the consequences if things go wrong.
Use skipfish only against services you own, or have a permission to test.
Use skipfish at your own risk.
source:http://linuxpoison.blogspot.com/2011/02/135781677510556.html