June 2000 - openSUSE Security - openSUSE Mailing Lists

SSH Authentication
by Joao Reis 18 Nov '02

18 Nov '02

Hi! I implemented a ssh conection from the outside to my intranet. This ssh requires a username and a password. In terms of security what is more secure: require authentication (username and password) or having the public key of each user that connects to our intranet in the authorized public key lists (in this case there is no need for username and password)? In the second case there is no need of authentication and only the users wich have the public keys in the list are allowed to enter in my intranet. This second solution is a good solution or that brings other security problems ? Thanks. -- Farewell. "Keep your friends close, but your enemies closer." "Do or do not. There is no try" - Yoda João Reis -------------------------------------------------------

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Re: is SuSE going to implement libsafe?
by marc＠suse.de 18 Feb '01

18 Feb '01

Hi, >I have just read an Bell Labs anouncement, that they are going to release >libsafe under GNU licence, and that some major Linux distros are going to >be using it. SuSE was not amongst them, why is that? I think that libsafe would >be a good echnacement against buffer overflow. > >Anouncement is on: >http://www.bell-labs.com/news/2000/april/20/1.html just because something new pops up please be careful with questions like "when will you implement it?" ;-) There are several questions to ask: a) is it STABLE and does it NOT affect the stability of other programs? b) does it bring additional security problems into the system? c) is the security protection effective? Well, of course the SuSE Security Team already reviewed libsafe. Here are the answers: a) unsure. it would have to be tested very intensive. this was not done yet. b) the code might have vulnerabilities, however the protection gained is higher even if a vulnerability would be present c) okay, now the tough part: libsafe is a dynamic library which is set in the environment which checks several dangerous functions, which can be a security problem. Because it is a dynamic library, it is NO protection against local attackers, just against remote attackers on network services. (if an attacker wants to attack a local suid file, he would just reset his library path environment). Next thing: it does not check for all known vulnerabilites. It even doesn't protect against all buffer overflows, It just protects against *some* overflows. those which happen because of insecure use of strcat/strcpy etc. summary: I can not remember a vulnerability in a network service for the last year which this tool would have prevented. Therefore: as long as this tool is not enhanced to also protect open/fopen calls against symlink/hardlink/pipe attacks, several more buffer overflow types, system/exec* function protection etc. it is not useful to use this tool. I would rather propose to use the secumod module which comes with SuSE Linux since 6.3 and maybe the secure-linux kernel patch from www.openwall.com - these two tools enhance your security. (and btw, install seccheck, hardensuse and firewals and use them - then your security is very high) Greets, Marc -- Marc Heuse, SuSE GmbH, Schanzaeckerstr. 10, 90443 Nuernberg E@mail: marc(a)suse.de Function: Security Support & Auditing "lynx -source http://www.suse.de/~marc/marc.pgp | pgp -fka" Key fingerprint = B5 07 B6 4E 9C EF 27 EE 16 D9 70 D4 87 B5 63 6C

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multi-services server securing
by Gediminas Grigas 16 Aug '00

16 Aug '00

Hello there, I feel erroneusly (?) secure after .host.denyed in.telnetd and in.sshd from everywhere except one pc, which is denying all exept keyboard. I belive that if i can keep hosts.deny and hosts.allow files safe, and from time to time patch most actual security holes i`ll be conditionaly safe. Em i wrong? Probably I do. I just cant imaginate how system can be cracked in lower stage, so that is my problem. I heard that inetd is very insecure, and some peoples using tcpd (or soundlike). I run harden_suse, but was forced to answer 8/10 to no, as my server should provide a lot of public services, and have world writible directories as well. And thats right - this script was developed not for systems like mine one. However i`ll run SuSE-firewall-3.0 script, to make my system even stronger. But thats all. I dont know what can i do else. I should keep folowing services open: httpd; smptd; pop3d; ftpd; snmpd; named; inetd; sshd; nscd. So if you know how to keep them at minimal risk, or know some holes at those, i would be very gratefull for any info and/or tips. I dont ask to do work for me - link to good manual would be nice too. By the way i have SuSE 6.3 (2.2.13). Thanks in advice. Sincerely Yours, Gediminas Grigas mailto:gedas@kryptis.lt

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hardensuse <-> procmail
by Walter Krohe 04 Jul '00

04 Jul '00

Hi ! Does the hardensuse script something wich make the mails in /var/spool/mail set to chmod 600 ? Sometimes I see in /var/log/warn: procmail[20002]: Insufficient privileges to deliver to "root" or similar. chmod 660 "by hand" -> /var/log/mail: procmail[22902]: Enforcing stricter permissions on "/var/spool/mail/root" Where can can I reset this behavior or is there a solution? Thanks for assistance. -- Walter Krohe, wk(a)u2me.de Schwabstrasse 20, D-73760 Ostfildern voice +49 711 3428 926, fax +49 711 3428 928

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SuSE Security Announcement: kernel-2.2.x
by thomas＠suse.de 04 Jul '00

04 Jul '00

-----BEGIN PGP SIGNED MESSAGE----- ______________________________________________________________________________ SuSE Security Announcement Package: kernel < 2.2.16 Date: Tue Jun 27 13:31:38 MEST 2000 Affected SuSE versions: 6.1-6.4 Vulnerability Type: local compromise of setuid applications SuSE default package: yes ______________________________________________________________________________ A security hole was discovered in the package mentioned above. Please update it 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 The implementation of the capability feature of the kernel 2.2.x < 2.2.16 is faulty. 2. Impact This bug allows an local adversary to exploit certain setuid applications to increase his/her privileges. 3. Solution We are sorry about the late release of the new kernel, but the plain 2.2.16 kernel causes trouble with our patches and it also has a new security hole. After we solved all these problems, we hope, we could provide you with a more stable and more secure kernel. Please, update the package from our FTP server. (These RPMs could also be used by SuSE Releases < 6.4!) The Alpha kernel will be released within the next days. The PPC kernel could be build from lx_suse.rpm _____________________________________________________________________________ Please verify these md5 checksums of the updates before installing: i386 Kernel Images: c089568d3d6a9f0826146f9204a37888 ftp.suse.com/pub/suse/i386/update/6.4/kernel-2.2.16/k_deflt.rpm f454d629ccdf49e98fe759448ac1d34b ftp.suse.com/pub/suse/i386/update/6.4/kernel-2.2.16/k_eide.rpm 0c7111d249482920bb4a14a59ea1dbc2 ftp.suse.com/pub/suse/i386/update/6.4/kernel-2.2.16/k_i386.rpm Laptop Kernel Images: 3faa2d00ab77ce0c336fc8fa9d4dee11 ftp.suse.com/pub/suse/i386/update/6.4/kernel-2.2.16/k_laptop.rpm SMP Kernel Images: 45b9cd13f61e1cf0b82b8b2d847650c9 ftp.suse.com/pub/suse/i386/update/6.4/kernel-2.2.16/k_smp.rpm SuSE Kernel Source Code: 41bde34659d93214af2cf5da6e7e2896 ftp.suse.com/pub/suse/i386/update/6.4/kernel-2.2.16/lx_suse.rpm PPC Patches: b9c8008eec0922a06c95be7c76f4da8e ftp.suse.com/pub/suse/i386/update/6.4/kernel-2.2.16/patch_collection.tar.gz ______________________________________________________________________________ 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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[suse-security] DialUp with Firewall
by Timo Schulz 02 Jul '00

02 Jul '00

Hello list, I have a little problem with my dialup connection. After I get connect, I have to restart the SuSEfirewall script to activate the PPP device. So I need root privilegs. Is there any secure possibility to restart the firewall without involving root? Thanks in advance. -- Two-a-Day at joesixpack.net www.freenet.de/joesixpack keyid BF3DF9B4

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suid and suse 6.4
by alex medvedev 30 Jun '00

30 Jun '00

hallo, so much for file permissions, but: alexm@quake:/ > id uid=1000(alexm) gid=100(users) groups=100(users) alexm@quake:/ > ls -l sh -rwsr-xr-x 1 root root 387764 Jun 28 00:27 sh* alexm@quake:/ > ./sh alexm@quake:/ > id uid=1000(alexm) gid=100(users) groups=100(users) :-o wasn't i supposed to get euid of root? or does suse's /bin/sh do some checks i am not aware of? thanks, -alexm P.S. btw, just checked it with /usr/bin/ksh and it does give the euid 0.

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RE: [suse-security] Auditing software for Squid
by Takács Attila 30 Jun '00

30 Jun '00

> asked to get accurate information on proxy usage based on users' ID. > I've been trying "calamaris" for this task, but it seems unable to > extract any info based on users (each line in the Squid logs includes > the name of the user). > > Any idea of what's happening? Maybe should I use > another software? >From the manual: -u user: Switches the usage of eventually available ident information for requester reports on. laazy

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logfiles
by engelbert gruber 30 Jun '00

30 Jun '00

why do the log files have permisssions set to 644 and not 600 ? -- engelbert gruber email: engelbert.gruber(a)ssg.co.at

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Is PAM the culprit?
by samarthax＠pobox.com 30 Jun '00

30 Jun '00

I have the following problem: adding a login account, deleting it, adding the same name again will lock the user name out with the above message. After deleting it, I made sure that the user home directory is gone, the entries in /etc/passwd, group and shadow for this user are gone. Then, when I add the same user name again, I cannot use the graphical logon window - I geht the "Xsession: login for <user> is disabled" - message box prompting me to click "OK" - Bs - it's not OK!!! I think there is somewhere an entry remaining in some auth database and the authentication fails. My syslog entry: Jun 29 01:27:50 munich PAM-unix2[18442]: session started for user sam2, service xdm Jun 29 01:28:00 munich PAM-unix2[18442]: session finished for user sam2, service xdm the /etc/pam.d/xdm has: #%PAM-1.0 auth required /lib/security/pam_unix.so nullok #set_secrpc account required /lib/security/pam_unix.so password required /lib/security/pam_unix.so #strict=false session required /lib/security/pam_unix.so debug # trace or none and I suspect that the session somehow fails. But I have no clue where the user information is kept in PAM. It is on SuSE 6.4 Samartha

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