Date: Mon, 05 Dec 2011 14:44:47 -0500 From: Mike Tancsa <mike@sentex.net> To: d@delphij.net Cc: "freebsd-security@freebsd.org" <freebsd-security@freebsd.org>, Xin LI <delphij@delphij.net>, Przemyslaw Frasunek <przemyslaw@frasunek.com> Subject: Re: ftpd security issue ? Message-ID: <4EDD1F2F.20802@sentex.net> In-Reply-To: <4ED6D577.9010007@delphij.net> References: <4ED68B4D.4020004@sentex.net> <4ED69B7E.50505@frasunek.com> <4ED6C3C6.5030402@delphij.net> <4ED6D1CD.9080700@sentex.net> <4ED6D577.9010007@delphij.net>
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On 11/30/2011 8:16 PM, Xin LI wrote: > On 11/30/11 17:01, Mike Tancsa wrote: >> On 11/30/2011 7:01 PM, Xin LI wrote: >>> >>>> BTW. This vulnerability affects only configurations, where >>>> /etc/ftpchroot exists or anonymous user is allowed to create >>>> files inside etc and lib dirs. >>> >>> This doesn't seem to be typical configuration or no? > >> I think in shared hosting environments it would be somewhat common. >> For annon ftp, I dont think the anon user would be able to create / >> write to a lib directory. > >>> >>> Will the attached patch fix the problem? >>> >>> (I think libc should just refuse /etc/nsswitch.conf and libraries >>> if they are writable by others by the way) > >> It does not seem to prevent the issue for me. Using Przemyslaw >> program's, > > Sorry I patched at the wrong place, this one should do. > > Note however this is not sufficient to fix the problem, for instance > one can still upload .so's that run arbitrary code at his privilege, > which has to be addressed in libc. I need some time to play around > with libc to really fix this one. Forgive the naive question, but is there a way to prevent a process (in this case proftpd) from loading a .so if the session is in a chrooted environment ? Or if at the start of the process, is there a way to force the process to load a lib so that later on, it wont try and load the "bad" lib ? ---Mike -- ------------------- Mike Tancsa, tel +1 519 651 3400 Sentex Communications, mike@sentex.net Providing Internet services since 1994 www.sentex.net Cambridge, Ontario Canada http://www.tancsa.com/
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