Date: Sun, 7 May 2017 20:47:39 +0200 From: Salvatore Bonaccorso <carnil@...ian.org> To: oss-security@...ts.openwall.com Subject: Re: rpcbomb: remote rpcbind denial-of-service Hi On Fri, May 05, 2017 at 11:52:49AM +0200, Florian Weimer wrote: > On 05/05/2017 11:22 AM, Marcus Meissner wrote: > > On Wed, May 03, 2017 at 05:55:20PM -0700, Seth Arnold wrote: > > > On Wed, May 03, 2017 at 08:55:23PM +0200, Guido Vranken wrote: > > > > This vulnerability allows an attacker to allocate any amount of bytes > > > > (up to 4 gigabytes per attack) on a remote rpcbind host, and the > > > > memory is never freed unless the process crashes or the administrator > > > > halts or restarts the rpcbind service. > > > > [...] > > > > An extensive write-up can be found here: > > > > https://guidovranken.wordpress.com/2017/05/03/rpcbomb-remote-rpcbind-denial-of-service-patches/ > > > > > > > > Exploit + patches: https://github.com/guidovranken/rpcbomb/ > > > > > > Hello Guido, nice find. Have CVE numbers been requested for this issue > > > yet? Have you investigated if ntirpc is affected too? Much of the code > > > looks similar: > > > > > > http://sources.debian.net/src/ntirpc/1.4.3-3/src/rpc_generic.c/#L728 > > > > We also saw glibc affected. > > > > https://bugzilla.suse.com/show_bug.cgi?id=1037559#c7 > > > > That said, your reproducer allocates virtual memory, and on systems with overcommit > > there is only neglible impact on overall memory pressure. > > > > The rpc service will however likely crash at some point though when there is no virtual > > address space left for it. > > Thanks, I filed it upstream as well: > > https://sourceware.org/bugzilla/show_bug.cgi?id=21461 > > Looks like both xdr_bytes and xdr_string have a similar bug. > > I'd appreciate some guidance on reusing or not reusing CVE IDs here. A separate CVE should be used for this issue as clarified with MITRE. It was assigned CVE-2017-8804. https://sourceware.org/bugzilla/show_bug.cgi?id=21461 Patch posted at https://sourceware.org/ml/libc-alpha/2017-05/msg00105.html by Florian Weimer. Regards, Salvatore
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