-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 ______________________________________________________________________________ SCO Security Advisory Subject: OpenServer 5.0.5 OpenServer 5.0.6 OpenServer 5.0.7 : REVISED: remote buffer overflow in sendmail (CERT CA-2003-07) Advisory number: CSSA-2003-SCO.6.2 Issue date: 2003 April 23 Cross reference: CSSA-2003-SCO.6 CSSA-2003-SCO.6.1 ______________________________________________________________________________ 1. Problem Description From CA-2003-07: Researchers at Internet Security Systems (ISS) have discovered a remotely exploitable vulnerability in sendmail. This vulnerability could allow an intruder to gain control of a vulnerable sendmail server. This update adds post installation instructions for the following issues: After installing CSSA-2003-SCO.6.1, the anti-relaying functionality does not work anymore. After installing CSSA-2003-SCO.6.1, the access database is not used. 1a. Post Installation Instructions The CSSA-2003-SCO.6.1 security fix does not replace your /usr/lib/sendmail.cf file; the orginal sendmail.cf file is left in place. There is a new sendmail.cf file that gets installed on the system, but it must be put in place and reconfigured. First, create a backup of your existing /usr/lib/sendmail.cf file: # cp /usr/lib/sendmail.cf /usr/lib/sendmail.cf.orig Next, the updated sendmail.cf must be put in place. This new sendmail.cf is stored in the /opt/K/SCO/SendMail/8.11.0a/.softmgmt/var/lib/ directory. To put this new sendmail.cf file in place run these commands: # cd /opt/K/SCO/SendMail/8.11.0a/.softmgmt/var/lib/ # cp sendmail.cf /usr/lib/sendmail.cf Now the sendmail.cf file must be reconfigured with information about your specific system. To do this run through "mkdev cf" and make sure all settings are correctly established. After configuring all the settings for your sendmail.cf file, generate a new sendmail.cf (selection 8 from the main mkdev cf menu). This will also restart sendmail, so the new changes will take effect without the system needed to be rebooted. Now that the new version of Sendmail is installed, the anti-relaying functionality is already in place by default. Mail cleints may be receiving access denied or relaying denied messages. This new version of sendmail uses a different anti-relaying database than previous versions of Sendmail that came with OpenServer 5.0.6 and before. This new functionality will work on OpenServer 5.0.6 and 5.0.5, with this new security fix in place. This new version of Sendmail uses the /usr/lib/mail/access file to specify trusted hosts and known spammers. This process is fully documented here: http://docsrv.caldera.com:8507/en/MailMsgG/sndmlCspam.html This /usr/lib/mail/access file is empty by default. But a sample of this file is: cyberspammer.com ERROR:"550 We don't accept mail from spammers" okay.cyberspammer.com OK sendmail.org RELAY 128.32 RELAY 1:2:3:4:5:6:7 RELAY [127.0.0.3] OK [1:2:3:4:5:6:7:8] OK Where 128.32 is an entire subnet that can be allowed to relay through this system. Also, specific domains can be sent specific error messages as seen in the first line. For more information, read through the Managing Spam URL listed above. 2. Vulnerable Supported Versions System Binaries ---------------------------------------------------------------------- OpenServer 5.0.5 previous to sendmail 8.11.0a OpenServer 5.0.6 previous to sendmail 8.11.0a OpenServer 5.0.7 previous to sendmail 8.11.0a 3. Solution The proper solution is to install the latest packages. 4. OpenServer 5.0.5 4.1 Location of Fixed Binaries ftp://ftp.sco.com/pub/updates/OpenServer/CSSA-2003-SCO.6.2 4.2 Verification MD5 (sendmail.506.tar) = da105d0a82313ed19bc10b515467e93f md5 is available for download from ftp://ftp.sco.com/pub/security/tools 4.3 Installing Fixed Binaries Upgrade the affected binaries with the following sequence: 1) Download the sendmail.506.tar file (OpenServer 5.0.5 uses the 5.0.6 tar image) 2) Extract the files from the tar archive: tar xvf sendmail.506.tar 3) Remove the existing version of SendMail - Backup your /usr/lib/sendmail.cf file - Backup the contents of your existing /usr/lib/mail directory - Using custom, remove the existing version of SendMail - SCO OpenServer Enterprise System SCO OpenServer Enterprise System UNIX SCO OpenServer Enterprise System Mail Utilities - Choose the option to leave it loaded if you wish 4) Still using the custom command, specify an install from media images, and specify the security fix download directory (from step 2) as the location of the images. 5) Restore the appropriate files from your saved copies. 6) Refer to Section 1a (above). 5. OpenServer 5.0.6 5.1 Location of Fixed Binaries ftp://ftp.sco.com/pub/updates/OpenServer/CSSA-2003-SCO.6.2 5.2 Verification MD5 (sendmail.506.tar) = da105d0a82313ed19bc10b515467e93f md5 is available for download from ftp://ftp.sco.com/pub/security/tools 5.3 Installing Fixed Binaries Upgrade the affected binaries with the following sequence: 1) Download the sendmail.506.tar 2) Extract the files from the tar archive: tar xvf sendmail.506.tar 3) Run the custom command, specify an install from media images, and specify the downloaded directory as the location of the images. 4) Refer to Section 1a (above). 6. OpenServer 5.0.7 6.1 Location of Fixed Binaries ftp://ftp.sco.com/pub/updates/OpenServer/CSSA-2003-SCO.6.2 6.2 Verification MD5 (sendmail.507.tar) = 807f1fa8d15a3361a589119bfca18533 md5 is available for download from ftp://ftp.sco.com/pub/security/tools 6.3 Installing Fixed Binaries Upgrade the affected binaries with the following sequence: 1) Download the sendmail.507.tar file 2) Extract the files from the tar archive: tar xvf sendmail.507.tar 3) Run the custom command, specify an install from media images, and specify the downloaded directory as the location of the images. 4) Refer to Section 1a (above). 7. References Specific references for this advisory: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2002-1337 http://www.iss.net/issEn/delivery/xforce/alertdetail.jsp?oid=21950 http://www.cert.org/advisories/CA-2003-07.html http://www.kb.cert.org/vuls/id/398025 http://www.sendmail.org/8.12.8.html SCO security resources: http://www.sco.com/support/security/index.html This security fix closes SCO incidents sr875284, fz527484, erg712247. 8. Disclaimer SCO is not responsible for the misuse of any of the information we provide on this website and/or through our security advisories. Our advisories are a service to our customers intended to promote secure installation and use of SCO products. 9. Acknowledgements Internet Security Systems, Inc. discovered and researched this vulnerability. ______________________________________________________________________________ -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (SCO_SV) Comment: For info see http://www.gnupg.org iEYEARECAAYFAj6nCWIACgkQaqoBO7ipriGrwwCggm59oC1+yrJ/dqbW6fK005NZ cBEAnRK+fT7gim+8+aQVKph/sRGegRrR =yzeb -----END PGP SIGNATURE-----