oss-sec mailing list archives
Re: rpcbomb: remote rpcbind denial-of-service
From: Florian Weimer <fweimer () redhat com>
Date: Mon, 8 May 2017 20:32:21 +0200
On 05/07/2017 08:47 PM, Salvatore Bonaccorso wrote:
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/#L728We 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.
Note that we have a bit of a dispute here whether whether this is actually a vulnerability in the XDR code, or whether the caller is to blame.
Thanks, Florian
Current thread:
- rpcbomb: remote rpcbind denial-of-service Guido Vranken (May 03)
- Re: rpcbomb: remote rpcbind denial-of-service Seth Arnold (May 03)
- Re: rpcbomb: remote rpcbind denial-of-service Marcus Meissner (May 05)
- Re: rpcbomb: remote rpcbind denial-of-service Florian Weimer (May 05)
- Re: rpcbomb: remote rpcbind denial-of-service Salvatore Bonaccorso (May 07)
- Re: rpcbomb: remote rpcbind denial-of-service Florian Weimer (May 08)
- Re: rpcbomb: remote rpcbind denial-of-service Marcus Meissner (May 05)
- Re: rpcbomb: remote rpcbind denial-of-service Seth Arnold (May 03)