26972 2009-07-04 19:17:20 -0700 predictable random number generator used in web browsers 2015-09-24 10:49:16 -0700 1 1 1 Unclassified WebKit JavaScriptCore 528+ (Nightly build) All All RESOLVED DUPLICATE 41868 http://www.trusteer.com/temporary-user-tracking-in-major-browsers InRadar P2 Normal --- 1 michael.s.gilbert webkit-unassigned abarth ddkilzer jmalonzo oliver sam webkit-bug-importer oldest_to_newest 129819 0 michael.s.gilbert 2009-07-04 19:17:20 -0700 hello, it has been discovered that all of the major web browsers use a predictable pseudo-random number generator (PRNG). please see reference [0]. the robust solution is to switch to a provably unpredictable PRNG such as Blum Blum Shub [1,2]. [0] http://www.trusteer.com/temporary-user-tracking-in-major-browsers [1] Lenore Blum, Manual Blum, and Michael Shub, "A Simple Unpredictable Pseudo-Random Number Generator," SIAM Journal on Computing, volume 15, pages 364-383, May 1986. [2] http://rng.doesntexist.org/gmpbbs 129820 1 michael.s.gilbert 2009-07-04 19:28:09 -0700 this is already publicly disclosed, so there is no reason to restrict access to this report. however, it seems i can't uncheck the box to do that... 129822 2 abarth 2009-07-04 20:24:56 -0700 I have unchecked the box for you. 129826 3 sam 2009-07-04 21:24:27 -0700 This is only a problem on Windows at the moment, where we found the existing cryptographically secure PRNG to be a hefty performance regression on some tests (I believe it was the JS iBench test). Mac OS uses arc4random for all random numbers, which I believe is suitable, and is noted in the paper. I think we should probably just include arc4random in the tree and call it a day. 129828 4 michael.s.gilbert 2009-07-04 21:40:45 -0700 the paper does not mention webkit on linux. what is the status of the PRNG there? 1128500 5 webkit-bug-importer 2015-09-24 09:11:44 -0700 <rdar://problem/22839305> 1128527 6 ddkilzer 2015-09-24 10:49:16 -0700 Dupe: Bug 41868: [JSC] Math.random is predictable which may lead to cross-domain information leakage and temporary user tracking attacks *** This bug has been marked as a duplicate of bug 41868 ***