Date: Tue, 25 Jun 2019 09:46:39 -0400 From: Alex Gaynor <alex.gaynor@...il.com> To: oss-security@...ts.openwall.com Subject: Re: Thousands of vulnerabilities, almost no CVEs: OSS-Fuzz 20% was a completely made us number. Alex On Tue, Jun 25, 2019, 9:42 AM Bob Friesenhahn <bfriesen@...ple.dallas.tx.us> wrote: > On Mon, 24 Jun 2019, Alex Gaynor wrote: > > - Not having sooooo many vulnerabilities. While there's some dispute over > > just what % of the bugs that OSS-Fuzz and syzbot turn up are exploitable, > > there's no doubt that they find a _lot_ of them. Even if only 20% of > > OSS-Fuzz reports were truly exploitable vulnerabilities, that'd still be > >> 600 of them. We can't produce this many vulnerabilities and then try to > > clean up afterwards by finding them with fuzzing -- at some point the > > number of vulnerabilities simply overwhelms us. Tactics for reducing > > vulnerabilities in the first instance, like memory safe languages, are an > > important part of making this problem tractable. > > > > Do folks feel like there were important themes that this misses? > > I see the assumption that 20% of oss-fuzz reports are exploitable > vulnerabilities. Where does this percentage estimate come from? What > does it mean to be "exploitable"? > > From working on fixing oss-fuzz detected bugs in GraphicsMagick I see > that many/most of the issues are not significant from a security > standpoint, assuming that the software is deployed in a way suitable > for its level of exposure. Common issues include: > > * Huge uninitialized memory allocations (which do not really matter > under Linux since Linux does not reserve anything but virtual > memory space). > > * Consumption of uninitialized data (e.g. image data) which is not > used to make important decisions. This is usually due to unhandled > cases or error handling which does not quit immediately. > > * Tiny heap over-reads which are not past the bounds of the > underlying allocation. > > * Heap over-reads or over-writes which cause an immediate core dump. > > * Excessively slow code with the slowness emphasized by ASAN and > UBSAN code running vastly slower. The excessively slow code is not > necessarily noticeable in a normal compilation. > > * Memory leaks. > > * "undefined behavior" which nevertheless has a common behavior that > compilers have followed since the dawn of time. > > The most important thing that oss-fuzz contributes is a large > collection of files which cause problems for unfixed software such > that only the unaware or foolish do not update to fixed versions. > > Bob > -- > Bob Friesenhahn > bfriesen@...ple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ > GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ > Public Key, http://www.simplesystems.org/users/bfriesen/public-key.txt >
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