May 2002 - openSUSE Security - openSUSE Mailing Lists

Failure mode for SuSEfirewall_setup
by Albert Brandl 08 May '02

08 May '02

Hi! When the init script SuSEfirewall_setup fails, it just writes out a red "failed" and terminates. If you boot up your machine in runlevel 5 and do not closely watch the initialization, you don't realize that the firewall has not been set up sucessfully. Since SuSEfirewall_init calls /sbin/SuSEfirewall close, which allows no incoming traffic, this does not open the machine to the "world". But I'm not quite sure if this "failure mode" is the best possible solution. Any opinions? Best regards, Albert Brandl

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RE: [suse-security] Antwort: Re: Re: [suse-security] IPChains and IPTables
by Reckhard, Tobias 08 May '02

08 May '02

> ... if I have to ask google ... > ... why does this mailing-list exist ? ... To answer those questions that Google doesn't answer. > ... thought this mailing-list is to discuss different topics Yeah, I guess general discussion about security is also OK, as long as it doesn't stray too far from SuSE. However, I don't mean questions to which there are simple or unique answers, and instead discussions of opinions. Tobias

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Antwort: Re: Re: [suse-security] IPChains and IPTables
by BLeonhardt＠analytek.de 08 May '02

08 May '02

... if I have to ask google ... ... why does this mailing-list exist ? ... ... thought this mailing-list is to discuss different topics ... and not only for "Firewall-Experts" ... Regards, Bruno Leonhardt Michael Appeldorn An: suse-security(a)suse.com, BLeonhardt(a)analytek.de <appeldorn@codix Kopie: x.de> Thema: Re: Re: [suse-security] IPChains and IPTables 08.05.02 11:37 Bitte antworten an Appeldorn >... now I'm not sure if I did understand that right ... > >.. IP-Chains can analyze if a packet is permitted to "go to the target >system" or not ( if so, the packet will be dropped or routed ) >.. IP-Tables can analyze all packets and Flags ( SYN, FIN, etc. ) no matter >where the packets destination is ( if a rule will apply the packet will be >dropped or routed ) > >.. right so ?!?!??!?!??!?! not really. again ! ask google ! e.g : compare iptables ipchains here the first link in list http://www.oofle.com/iptables/comparison.htm Yours Michael Appeldorn

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SuSE Security Announcement: sysconfig (SuSE-SA:2002:016)
by Sebastian Krahmer 08 May '02

08 May '02

-----BEGIN PGP SIGNED MESSAGE----- ______________________________________________________________________________ SuSE Security Announcement Package: sysconfig Announcement-ID: SuSE-SA:2002:016 Date: Wed May 8 12:00:00 MEST 2002 Affected products: 8.0 Vulnerability Type: remote command execution Severity (1-10): 4 SuSE default package: Yes. Other affected systems: No. Content of this advisory: 1) security vulnerability resolved: Quotation problem in ifup-dhcp. problem description, discussion, solution and upgrade information 2) pending vulnerabilities, solutions, workarounds 3) standard appendix (further information) ______________________________________________________________________________ 1) problem description, brief discussion, solution, upgrade information The ifup-dhcp script which is part of the sysconfig package is responsible for setting up network-devices using configuration data obtained from a DHCP server by the dhcpcd DHCP client. It is possible for remote attackers to feed this script with evil data via spoofed DHCP replies for example. This way ifup-dhcp could be tricked into executing arbitrary commands as root. The ifup-dhcp shellscript has been fixed to not source the file containing the possible evil data anymore. Even though the sysconfig package is installed by default, this problem only affects systems with certain dhcp network-setups so only users using DHCP should update their sysconfig package. Please download the update package for your distribution and verify its integrity by the methods listed in section 3) of this announcement. Then, install the package using the command "rpm -Fhv file.rpm" to apply the update. Our maintenance customers are being notified individually. The packages are being offered to install from the maintenance web. i386 Intel Platform: SuSE-8.0 ftp://ftp.suse.com/pub/suse/i386/update/8.0/a1/sysconfig-0.23.14-60.i386.rpm 4d6a9f1a3e1a461ebbea9a6e98f4e894 source rpm: ftp://ftp.suse.com/pub/suse/i386/update/8.0/zq1/sysconfig-0.23.14-60.src.rpm d0fdfe02cfc9b7fc32fed8da6c16cf9d ______________________________________________________________________________ 2) Pending vulnerabilities in SuSE Distributions and Workarounds: - mozilla/netscape The mozilla browser in version 0.9.7 or higher and the netscape browser in version 6.1 or higher contain a flaw which allows remote sites to read arbitrary files if the user running the browser has the permission to do so. Fixed packages for the mozilla browser will be available soon on our ftp-servers. Patches for the affected netscape browser are not yet available due to missing fixes from Netscape. - xpilot It has been reported that the xpilot server contains a buffer-overflow which allows remote attackers to execute arbitrary commands as the user running the server. The overflow has been fixed and new xpilot packages are available on our ftp-servers. Please update to the newest xpilot packages if you used to run this program. ______________________________________________________________________________ 3) standard appendix: authenticity verification, additional information - Package authenticity verification: SuSE update packages are available on many mirror ftp servers all over the world. While this service is being considered valuable and important to the free and open source software community, many users wish to be sure about the origin of the package and its content before installing the package. There are two verification methods that can be used independently from each other to prove the authenticity of a downloaded file or rpm package: 1) md5sums as provided in the (cryptographically signed) announcement. 2) using the internal gpg signatures of the rpm package. 1) execute the command md5sum <name-of-the-file.rpm> after you downloaded the file from a SuSE ftp server or its mirrors. Then, compare the resulting md5sum with the one that is listed in the announcement. Since the announcement containing the checksums is cryptographically signed (usually using the key security(a)suse.de), the checksums show proof of the authenticity of the package. We disrecommend to subscribe to security lists which cause the email message containing the announcement to be modified so that the signature does not match after transport through the mailing list software. Downsides: You must be able to verify the authenticity of the announcement in the first place. If RPM packages are being rebuilt and a new version of a package is published on the ftp server, all md5 sums for the files are useless. 2) rpm package signatures provide an easy way to verify the authenticity of an rpm package. Use the command rpm -v --checksig <file.rpm> to verify the signature of the package, where <file.rpm> is the filename of the rpm package that you have downloaded. Of course, package authenticity verification can only target an uninstalled rpm package file. Prerequisites: a) gpg is installed b) The package is signed using a certain key. The public part of this key must be installed by the gpg program in the directory ~/.gnupg/ under the user's home directory who performs the signature verification (usually root). You can import the key that is used by SuSE in rpm packages for SuSE Linux by saving this announcement to a file ("announcement.txt") and running the command (do "su -" to be root): gpg --batch; gpg < announcement.txt | gpg --import SuSE Linux distributions version 7.1 and thereafter install the key "build(a)suse.de" upon installation or upgrade, provided that the package gpg is installed. The file containing the public key is placed at the toplevel directory of the first CD (pubring.gpg) and at ftp://ftp.suse.com/pub/suse/pubring.gpg-build.suse.de . - SuSE runs two security mailing lists to which any interested party may subscribe: suse-security(a)suse.com - general/linux/SuSE security discussion. All SuSE security announcements are sent to this list. To subscribe, send an email to <suse-security-subscribe(a)suse.com>. suse-security-announce(a)suse.com - SuSE's announce-only mailing list. Only SuSE's security annoucements are sent to this list. To subscribe, send an email to <suse-security-announce-subscribe(a)suse.com>. For general information or the frequently asked questions (faq) send mail to: <suse-security-info(a)suse.com> or <suse-security-faq(a)suse.com> respectively. ===================================================================== SuSE's security contact is <security(a)suse.com> or <security(a)suse.de>. The <security(a)suse.de> public key is listed below. ===================================================================== ______________________________________________________________________________ The information in this advisory may be distributed or reproduced, provided that the advisory is not modified in any way. In particular, it is desired that the cleartext signature shows proof of the authenticity of the text. SuSE GmbH makes no warranties of any kind whatsoever with respect to the information contained in this security advisory. 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Re: Re: [suse-security] IPChains and IPTables
by BLeonhardt＠analytek.de 08 May '02

08 May '02

Hi again, I 've read the pages ... ... now I'm not sure if I did understand that right ... .. IP-Chains can analyze if a packet is permitted to "go to the target system" or not ( if so, the packet will be dropped or routed ) .. IP-Tables can analyze all packets and Flags ( SYN, FIN, etc. ) no matter where the packets destination is ( if a rule will apply the packet will be dropped or routed ) .. right so ?!?!??!?!??!?! Thanks ! Regards, Bruno Leonhardt Michael Appeldorn An: suse-security(a)suse.com, BLeonhardt(a)analytek.de <appeldorn@codix Kopie: x.de> Thema: Re: [suse-security] IPChains and IPTables 07.05.02 11:34 Bitte antworten an Appeldorn Hi all, > >what exactly are the main differences between IPChains and IPTables ? > ask google 4: difference ipchains iptables snip ------ Message-ID: <EB5EB93D190ED31180430008C7F3714DB4A503@COSEXCH> From: "Woodworth, Lora" <Lora.Woodworth(a)cta.com> To: "'security-discuss(a)linuxsecurity.com'" <security-discuss(a)linuxsecurity.com> Subject: RE: Difference in ipchains and iptable Date: Wed, 31 Oct 2001 10:32:35 -0700 In short and in general iptables is in the 2.4 Kernel and will allow you to build a stateful firewall. ipchains was in 2.2 Kernel and gives you a stateless firewall. There is a good article about building an iptables based firewall at: http://www.linuxworld.com/site-stories/2001/0920.ipchains.html Also if you want more information do a search at: http://www.linuxsecurity.com and it has quite a few links. ------ snap Yours Michael Appeldorn -- To unsubscribe, e-mail: suse-security-unsubscribe(a)suse.com For additional commands, e-mail: suse-security-help(a)suse.com Security-related bug reports go to security(a)suse.de, not here

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Re: [suse-security] IPChains and IPTables
by Peer Stefan 08 May '02

08 May '02

Hi, > From: BLeonhardt(a)analytek.de [mailto:BLeonhardt@analytek.de] > .. IP-Chains can analyze if a packet is permitted to "go to the target > system" or not ( if so, the packet will be dropped or routed ) yes. that's right. > .. IP-Tables can analyze all packets and Flags ( SYN, FIN, > etc. ) no matter where the packets destination is ( if a > rule will apply the packet will be dropped or routed ) basically yes. as far as this is concerned, ipchains and iptables are similar. packets, which arrive at the iptables/ipchains-host are dropped, rejected, accepted, forwarded ... according to the rules. ipchains also understands syn-flags: #ipchains -h ... [!] --syn -y match TCP packets only when SYN set ... # one main difference is, iptables keeps track of existing connections (connection-states). you may apply rules according to the state of the connection (NEW,ESTABLISHED,...), which may come in handy with udp-connections, since there are no such things as syns. > Thanks ! you're welcome :-) > Regards, > Bruno Leonhardt regards, stefan

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RE: Telnet Proxy
by d_lord＠gmx.de 07 May '02

07 May '02

Hi Martin, Your telnet problem could be solved in two ways with a shell script as "login shell" as mentioned befor. - real proxy, the firewall opens the telnet connection to the host specified - forwarding over ipchains/iptables rule Greetings D. Lord -- GMX - Die Kommunikationsplattform im Internet. http://www.gmx.net

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Telnet-Proxy
by Martin Sckopke 07 May '02

07 May '02

Hi all, has anybody ever heard of a telnet-proxy? Checkpoints Firewall-1 offers this kind of functionality: You connect to the firewall on port 23, firewall asks for authentification and a hostname and afterwards you get a transparent telnet session to the named host, without any intererence by the firewall. Is something like that available as open source software? Thanks a lot, Martin

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IPChains and IPTables
by BLeonhardt＠analytek.de 07 May '02

07 May '02

Hi all, what exactly are the main differences between IPChains and IPTables ? Is it true that IPChains is only able to work as packet-filter ( like destination : port forbidden ) ? Regards, Bruno Leonhardt

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blocking certain ips
by Mike Otto 07 May '02

07 May '02

SuSEfirewall2 v2.1 iptables v1.2.5 Linux-Kernel 2.4.18 (5) ------------------------- Hi I´m looking for a way to block certain IP Addresses from all ports on my computer. I tried this at the console: iptables -A FORWARD -p tcp -s 192.168.100.1 -d 0.0.0.0/0.0.0.0 --dport 80 -j DROP but i can still connect from 192.168.100.1 to port 80 with telnet. Do I have to activate this rule first? or does it have to fit into firewall2-custom.rc.config, then restart firewall? Regards, Mike

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