[FUGSPBR] Falha no Free fornece acesso remoto

Luis Vitorio Cargnini lvcargnini em telenova.net
Sex Ago 9 08:05:36 BRT 2002


Isso e um falahoa do nivel de apresentacao do RPC e ja e conhecido faz
algum tempo isso e afeta todos os sistemaS que usarem nfs baseado no
mopdelo da Sun
On Fri, 2002-08-09 at 13:25, sandro luiz silva wrote:
> 
> ---------- Forwarded Message -----------
> From: "sandro luiz silva" <sandro em cacer.com.br>
> To: "lista fugsbr" <fugspbr em fugspbr.org>
> Sent: Fri, 9 Aug 2002 10:15:35 -0300
> Subject: OFF Topic Falha no Free fornece acesso remoto
> 
> Noticias retirados do site infoexame
> 
> TI 
> Bug afeta Windows, Linux e Mac OS e FreeBSD 
> Uma falha de segurança localizada numa biblioteca chamada XDR afeta diversos 
> sistemas operacionais, incluindo Windows, Linux, Mac OS e Solaris.  
> 
> Acessem também
> 
> ftp://ftp.freebsd.org/pub/FreeBSD/CERT/advisories/FreeBSD-SA-02:34.rpc.asc
> 
> -----BEGIN PGP SIGNED MESSAGE-----
> 
> =============================================================================
> FreeBSD-SA-02:34.rpc                                        Security Advisory
>                                                           The FreeBSD Project
> 
> Topic:          Sun RPC XDR decoder contains buffer overflow
> 
> Category:       core
> Module:         libc
> Announced:      2002-08-01
> Credits:        ISS X-Force
> Affects:        All releases of FreeBSD up to and including 4.6.1-RELEASE-p5
> Corrected:      2002-08-01 12:23:20 UTC (RELENG_4)
>                 2002-08-01 12:23:40 UTC (RELENG_4_6)
>                 2002-08-01 12:23:58 UTC (RELENG_4_5)
>                 2002-08-01 12:24:20 UTC (RELENG_4_4)
> FreeBSD only:   NO
> 
> 0.   Revision History
> 
> v1.0  2002-07-31  Initial release
> v1.1  2002-08-01  Corrected patch
> 
> I.   Background
> 
> Sun RPC is a remote procedure call framework which allows clients
> to invoke procedures in a server process over a network somewhat
> transparently.  XDR is a mechanism for encoding data structures for
> use with RPC.  NFS, NIS, and many other network services are built
> upon Sun RPC.
> 
> The FreeBSD C runtime library (libc) contains an XDR encoder/decoder
> derived from Sun's RPC implementation.
> 
> II.  Problem Description
> 
> An error in the calculation of memory needed for unpacking arrays in
> the XDR decoder can result in a heap buffer overflow.
> 
> III. Impact
> 
> Any application using Sun RPC may be vulnerable to the heap buffer
> overflow.  Depending upon the application, this vulnerability may be
> exploitable and lead to arbitrary code execution.
> 
> Though no exploits are known to exist currently, many RPC-based
> services run as the superuser (such as NFS, the NIS server, rpc.statd,
> and others) and thus this vulnerability should be considered
> high-risk.
> 
> No RPC-based services are enabled by default in FreeBSD installations.
> 
> IV.  Workaround
> 
> Do not run any RPC-based services.  The RPC-based services running
> on a machine may be determined by:
> 
>   # rpcinfo -p <hostname>
> 
> To disable any RPC-based services at next boot, add (or change if it
> is already present) the following lines in /etc/rc.conf:
> 
>   portmap_enable="NO"
>   nfs_client_enable="NO"
>   nfs_server_enable="NO"
>   nis_client_enable="NO"
>   nis_server_enable="NO"
> 
> V.   Solution
> 
> Do one of the following:
> 
> 1) Upgrade your vulnerable system to 4.6-STABLE; or to the RELENG_4_6,
> RELENG_4_5, or RELENG_4_4 security branch dated after the correction
> date (4.6.1-RELEASE-p6, 4.5-RELEASE-p15, or 4.4-RELEASE-p22).
> 
> 2) To patch your present system:
> 
> The following patch has been verified to apply to FreeBSD 4.4, 4.5,
> and 4.6 systems.
> 
> a) Download the relevant patch from the location below, and verify the
> detached PGP signature using your PGP utility.
> 
> # fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-02:34/rpc.patch
> # fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/CERT/patches/SA-02:34/rpc.patch.asc
> 
> b) Execute the following commands as root:
> 
> # cd /usr/src
> # patch < /path/to/patch
> 
> c) Recompile the operating system as described in
> <URL:http://www.freebsd.org/doc/handbook/makeworld.html>.
> 
> Note that any statically linked applications that are not part of
> the base system (i.e. from the Ports Collection or other 3rd-party
> sources) must be recompiled if they use Sun RPC.
> 
> All affected applications must be restarted in order to use the
> corrected library.  Though it is not required, rebooting may be the
> easiest way to accomplish this.
> 
> VI.  Correction details
> 
> The following list contains the revision numbers of each file that was
> corrected in FreeBSD.
> 
> Path                                                             Revision
>   Branch
> - -------------------------------------------------------------------------
> src/lib/libc/xdr/xdr_array.c
>   RELENG_4                                                        1.8.2.3
>   RELENG_4_6                                                     1.8.10.4
>   RELENG_4_5                                                      1.8.8.3
>   RELENG_4_4                                                      1.8.6.3
> src/sys/conf/newvers.sh
>   RELENG_4_6                                               1.44.2.23.2.11
>   RELENG_4_5                                               1.44.2.20.2.16
>   RELENG_4_4                                               1.44.2.17.2.21
> - -------------------------------------------------------------------------
> 
> VII. References
> 
> <URL:http://online.securityfocus.com/archive/1/285308>
> <URL:http://bvlive01.iss.net/issEn/delivery/xforce/alertdetail.jsp?oid=20823>
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> 
> ----
> Sandro Luiz Silva
> Analista de Sistema
> Fone: 047 9952-4876
> ------- End of Forwarded Message -------
> 
> 
> ----
> Sandro Luiz Silva
> Analista de Sistema
> Fone: 047 9952-4876
> ________________________________________________
> Para sair da lista visite o URL abaixo:
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> 
-- 
Thanks && Regards
Luís Vitório Cargnini 
TRDC - Telenova Communications Corp. 
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