WebApp Sec mailing list archives
Re: Ruining Security with java.util.Random
From: Amit Klein <aksecurity () gmail com>
Date: Tue, 19 Dec 2006 08:21:08 +0200
Jan P. Monsch wrote:
FYI: I discussed a particular case of reconstructing the internal PRNG state from output observation (the Apache JServ session ID weakness - which is based on the Java Random) in my "Cookie Poisoning" paper of 2002 (http://www.cgisecurity.com/lib/CookiePoisoningByline.pdf, see the appendix for details).Hi In my review practice I often have to look at Java source code which is used to generate passwords, authentication tokens or session ids. Ever so often this code uses the Java API class java.util.Random to generate random numbers. It is well-established in security industry that this particular random generator is not secure. Since I did not know what the reason is for this perception I started to have a closer look. During the review of the Java API source code I discovered two vulnerabilities which cause the internal state of java.util.Random to be partially exposed or easy guessable. Following paper "Ruining Security with java.util.Random" demonstrates two techniques how security mechanisms based on java.util.Random can be attacked and under certain conditions can be broken within seconds: http://www.iplosion.com/papers/ruining_security_with_java.util.random_v1.0.pdf
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Current thread:
- Ruining Security with java.util.Random Jan P. Monsch (Dec 18)
- Re: Ruining Security with java.util.Random Amit Klein (Dec 19)