May 2000 - openSUSE Security - openSUSE Mailing Lists

Re: [suse-security] temporary files created by crontab -e
by Eilert Brinkmann 04 May '00

04 May '00

"Petri Sirkkala." <petes(a)noitatieto.fi> wrote: > On Thu, 4 May 2000, Roland Hilkenbach wrote: > > > behavior can easily be used to do a DoS since the /tmp directory has the > > sticky-Bit set. > > What? No sticky bits are set at my installation. That would be a major > mistake allowing others to make files belonging to root:root. The permissions for /tmp should look like this: drwxrwxrwt 23 root root 5120 May 4 06:50 /tmp ^ The 't' indicates, that the sticky bit is set. In directories with the sticky bit set files can only be renamed or removed by their owner or by the owner of the directory (see `man 2 stat'). This bit *should* be set for world writable directories like /tmp. You have a security problem when it isn't, because then everybody could rename or unlink other user's files in /tmp. > Just think what these files could do, if made setuid too? You should > doublecheck your system, if someone has somehow made your tmp > setgid- or setuid something. AFAIR the setuid bit for directories doesn't have any effect on Linux systems. However, it is correct that neither the setuid nor the setgid bit should be set for /tmp, but that's something completely different than the sticky bit. Eilert -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Eilert Brinkmann -- Universitaet Bremen -- FB 3, Informatik eilert(a)informatik.uni-bremen.de - eilert(a)tzi.org - eilert(a)linuxfreak.com http://www.informatik.uni-bremen.de/~eilert/

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Re: [suse-security] Portscans
by christian.burri＠synecta.ch 04 May '00

04 May '00

ok, if you're freightened by portscans, you can run PORTSENTRY from www.psionic.com enjoy ;-) crisbie

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SuSE Security Announcement - aaa_base - UPDATE
by marc＠suse.de 04 May '00

04 May '00

-----BEGIN PGP SIGNED MESSAGE----- UPDATE INFORMATION The original announcement pointed to update rpms which were old and did *NOT* fix the vulnerabilities. We apologize for this mistake. ______________________________________________________________________________ SuSE Security Announcement Package: aaabase < 2000.5.2 Date: Tue May 2 21:56:21 CEST 2000 Affected SuSE versions: all Vulnerability Type: remove any local file(s) executing attacker supplied commands as non-root SuSE default package: yes Other affected systems: unknown ______________________________________________________________________________ A security hole was discovered in the package mentioned above. Please update as soon as possible or disable the service if you are using this software on your SuSE Linux installation(s). Other Linux distributions or operating systems might be affected as well, please contact your vendor for information about this issue. Please note that we provide this information on an "as-is" basis only. There is no warranty whatsoever and no liability for any direct, indirect or incidental damage arising from this information or the installation of the update package. _____________________________________________________________________________ 1. Problem Description aaa_base is the basic package which comes with any SuSE Linux installation. Two vulnerabilities have been found: 1) The cron job /etc/cron.daily/aaa_base does a daily checking of files in /tmp and /var/tmp, where old files will be deleted if configured to do so. Please note this this feature is NOT activated by default 2) Some system accounts have their homedirectories set to /tmp by default. These are the users games, firewall, wwwrun and nobody on a SuSE 6.4. 2. Impact 1) If the /tmp cleanup is activated, any file or directory can be deleted by any local user 2) If an attacker creates dot files in /tmp (e.g. bash profiles), these might be executed if someone uses e.g. "su - nobody" to switch to the nobody user. This can lead to a compromise of that userid. This vulnerability is present in several other unix systems as well - please check all! 3. Solution 1) Update the package from our FTP server. 2) The root user will receive a email with the accounts listed which have a homedirectory in /tmp. You have to fix this by hand, because some installations might break if they rely on information saved in the (unsafe) /tmp homedirectory. The email will give more information what to do. ______________________________________________________________________________ Please verify these md5 checksums of the updates before installing: (for SuSE 6.0 please use the 6.1 update rpm) a8204a4929c139e895f3357021647daa ftp://ftp.suse.com/pub/suse/axp/update/6.1/a1/aaa_base-2000.5.2-0.alpha.rpm 5dee42bd0f531922d0b17d859f3d0d0d ftp://ftp.suse.com/pub/suse/axp/update/6.3/a1/aaa_base-2000.5.2-0.alpha.rpm da8c74f80983beecf23baa62eea45142 ftp://ftp.suse.com/pub/suse/i386/update/6.1/a1/aaa_base-2000.5.2-0.i386.rpm 9618ec3ae63f4d80527a8e3b5f610fc1 ftp://ftp.suse.com/pub/suse/i386/update/6.2/a1/aaa_base-2000.5.2-0.i386.rpm db53e002b6be652b31262bf89be0c31a ftp://ftp.suse.com/pub/suse/i386/update/6.4/a1/aaa_base-2000.5.2-0.i386.rpm 488eda289876ba3c14dbffb881dc8726 ftp://ftp.suse.com/pub/suse/ppc/update/6.3/a1/aaa_base-2000.5.2-0.ppc.rpm ______________________________________________________________________________ You can find updates on our ftp-Server: ftp://ftp.suse.com/pub/suse/i386/update for Intel processors ftp://ftp.suse.com/pub/suse/axp/update for Alpha processors or try the following web pages for a list of mirrors: http://www.suse.de/ftp.html http://www.suse.com/ftp_new.html Our webpage for patches: http://www.suse.de/patches/index.html Our webpage for security announcements: http://www.suse.de/security If you want to report vulnerabilities, please contact security(a)suse.de ______________________________________________________________________________ SuSE has got two free security mailing list services to which any interested party may subscribe: suse-security(a)suse.com - moderated and for general/linux/SuSE security discussions. All SuSE security announcements are sent to this list. suse-security-announce(a)suse.com - SuSE's announce-only mailing list. Only SuSE's security annoucements are sent to this list. To subscribe to the list, send a message to: <suse-security-subscribe(a)suse.com> To remove your address from the list, send a message to: <suse-security-unsubscribe(a)suse.com> Send mail to the following for info and FAQ for this list: <suse-security-info(a)suse.com> <suse-security-faq(a)suse.com> _____________________________________________________________________________ This information is provided freely to everyone interested and may be redistributed provided that it is not altered in any way. 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x wrapper
by alex medvedev 03 May '00

03 May '00

hi, i installed suse's X 4.0. it does not start up for regular users because it requires root. in the error message while starting up it mentioned a wrapper for startup. i wrote one that is only one line: execv ("/usr/bin/X11/startx", NULL); and set it uid root. also, i unset the startx() function from the /etc/profile. is that the way one supposed to run X4.0? or is it at least secure? thanks, -alexm

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Re: SuSE 6.3 Gnomelib buffer overflow
by Thomas Biege 03 May '00

03 May '00

Hi, SuSE 6.3 includes just one SUGID gnome app and that's /opt/gnome/sbin/gnome-pty-helper, which is setgid tty. Only SuSE 6.4 includes setgid gnome games but it is _not_ vulnerable to this exploit. This bug doesn't depend on the Linux distributor, it depends on the gnome version. I think older releases of the other Linux vendors are also vulnerable... so, take care. We are working for a patch... stay tuned. Bye, Thomas -- Thomas Biege, SuSE GmbH, Schanzaeckerstr. 10, 90443 Nuernberg E@mail: thomas(a)suse.de Function: Security Support & Auditing "lynx -source http://www.suse.de/~thomas/thomas.pgp | pgp -fka" Key fingerprint = 09 48 F2 FD 81 F7 E7 98 6D C7 36 F1 96 6A 12 47

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freeS/WAN on SuSE 6.4
by Torsten Behle 03 May '00

03 May '00

Hi list, Please be careful when upgrading your freeS/WAN-machine to SuSE 6.4. As far as I can understand this, SuSE has compiled freeS/WAN 1.3 in the 6.4 edition, but did not apply the kernel-patches to the lx_suse kernel-sources. It works well with the standard kernel, but not if I want to recompile it. Given that very few people use a standard kernel on a firewall machine - what is the suggested way of installing freeS/WAN on SuSE 6.4? I installed freeS/WAN sources, but would like to benefit from the convenience the SuSE-team wanted to make available to us. BTW: Changing the location of the binaries to /usr//local/lib/ipsec/ to /usr/lib/ipsec/ has not been reflected in the hard coded $IPSECDIR in /usr/sbin/ipsec. If you don't change that, freeS/WAN even doesn't run on a standard SuSE-kernel. Also the manpage.d-directory for e.g. the ipsec.conf-html-manpage has not been built. Torsten Behle FCB/Wilkens Germany

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Re: [suse-security] password lenght limit
by Wild Karl-Heinz 03 May '00

03 May '00

There is an file in /etc it name is something like limits... There you can change the max length of a password. -- kh -----Original Message----- From: Thorsten Kukuk <kukuk(a)suse.de> To: jonathan <jfondow1(a)home.com> Cc: suse-security <suse-security(a)suse.com> Date: Samstag, 29. April 2000 17:14 Subject: Re: [suse-security] password lenght limit >On Sat, Apr 29, jonathan wrote: > >> I had a 12 character password on my firewall with 6.3, when I rebuilt > >I doubt that you had a 12 character password on your firewall. Unix allows >only 8 characters. Maybe you have always typed 12 characters, but it was >always truncated after the 8 character. > >> the system with 6.4 I am now limited to only 8 characters? Did I forget >> to load something or what is the problem? Thanx > >If you wish to use passwords up to 128 characters, you need to use >md5 hash sums for your password. > > Thorsten > >-- >Thorsten Kukuk http://www.suse.de/~kukuk/ kukuk(a)suse.de >SuSE GmbH Schanzaeckerstr. 10 90443 Nuernberg >Linux is like a Vorlon. It is incredibly powerful, gives terse, >cryptic answers and has a lot of things going on in the background. > >--------------------------------------------------------------------- >To unsubscribe, e-mail: suse-security-unsubscribe(a)suse.com >For additional commands, e-mail: suse-security-help(a)suse.com > > >

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ypbind not running - can still login
by Volker Kuhlmann 03 May '00

03 May '00

I did some tests with the NIS authentication stuff on SuSE 6.3, setting a ypserver and starting ypbind (both via /etc/rc.config). Package ypclient-3.4-4. I edited /etc/passwd and changed the default +:::::: to +someuser:::::: This should only allow someuser to login. Fine. Then I /etc/rc.d/init.d/ypclient stop to revert back to standard non-NIS behaviour. But user someuser can still login, using the password authenticated by the yp server. Putting a bogus ypserver into /etc/yp.conf has no effect, and there is no someuser anywhere else in passwd. This is a worry - I get NIS authentication but ypbind isn't running!! What's going on? Something must be buffered somewwhere - unloading ypbind should flush that!! Volker

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RE: [suse-security] Portscans
by Paul Kincaid 03 May '00

03 May '00

I realize this thread is a week old, but one package that no one talked about was Portsentry. It does not come bundled with SuSE, but its free out there -- just check http://www.freshmeat.net. I run both scanlogd and portsentry, and portsentry gets the most use. Most scans these days on the internet are to one port. I.e. a script kiddie will scan a whole subnet for one particular port being open. That will not get picked up by scanlog. As for scanlogd and being the specific target of someone - I have had great success with scanlog picking up the scans. Yes, there are some false positives, but not that many. I'm not going to get into the legal ramifications of port scanning someone... But I usually just contact the admin of the site if its obvious that it could be a compromised system (i.e. you usually don't get scanned from ns2.somewhere.com to port 23...) Also, if I get scanned, you are automatically dropped into a "reject" route in my routing table. If I see multiple attempts from the same site, I'll contact the ISP. Unfortunately as someone else said, its something that we'll probably just have to live with. Lock down your systems, keep up with the security threads, actively monitor your logs and you'll be fine. Just some of my thoughts... Paul Kincaid -----Original Message----- From: Timo Schulz [mailto:twoaday@gmx.de] Sent: Wednesday, April 26, 2000 9:07 AM To: SuSE Security Subject: [suse-security] Portscans Hi list, I have a few questions about the detection of port scanning. In the IX 5/May 2000 magazin (German), the author writes that he uses nmap to scan a well used web site. First I want to know if the victim can easily detect the scan and how to prevent such scans. Does SuSE 6.x contain any tools to do that ? PS: I ask me, if it is legal to do portscans on any sites ? -- Two-a-Day at joesixpack.net www.freenet.de/joesixpack keyid BF3DF9B4 --------------------------------------------------------------------- To unsubscribe, e-mail: suse-security-unsubscribe(a)suse.com For additional commands, e-mail: suse-security-help(a)suse.com

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chroot and NFS
by Security 02 May '00

02 May '00

trying to minimize the disc space in a chrooted environment, I found the only practical way in mounting the "big" trees /bin , /lib , /usr as NFS, exported from localhost. In doing so I have control about what my virtual server users can do and the security task is done well. So far everything works fine, BUT: there is a limit of 128 mounts (I need 300) My questions are: 1. how can I get 300 mounts from localhost on localhost? 2. is there another way to support "virtual" directories in an chrooted environment from "outer space (localhost)" I assume, localhost NFS is secure!? Thx 4 all help, Bernhard

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