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CERT Vendor Bulletin - HEWLETT-PACKARD SECURITY BULLETIN: #00025
CERT Vendor-Initiated Bulletin VB-95:03 April 12, 1995 Topic: Sendmail permits unauthorized remote program execution Source: Hewlett-Packard Company Related CERT documents: CA-95:05 and CA-94:12, "Sendmail Vulnerabilities" To aid in the wide distribution of essential security information, the CERT Coordination Center is forwarding the following information from Hewlett- Packard. HP urges you to act on this information as soon as possible. HP contact information is included in the forwarded text below; please contact them if you have any questions or need further information. ========================FORWARDED TEXT STARTS HERE============================ ------------------------------------------------------------------------- HEWLETT-PACKARD SECURITY BULLETIN: #00025, 2 April 95 ------------------------------------------------------------------------- The information in the following Security Bulletin should be acted upon as soon as possible. Hewlett- Packard will not be liable for any consequences to any customer resulting from customer's failure to fully implement instructions in this Security Bulletin as soon as possible. _______________________________________________________________________ PROBLEM: Sendmail permits unauthorized remote program execution. PLATFORM: HP 9000 series 300/400s and 700/800s 8.x and 9.x DAMAGE: Remote users can cause sendmail to execute any program. SOLUTION: Apply patch PHNE_5402 (series 700/800, HP-UX 9.x), or PHNE_5401 (series 700/800, HP-UX 8.x), or PHNE_5384 (series 300/400, HP-UX 9.x), or PHNE_5383 (series 300/400, HP-UX 8.x), or PHNE_5387 (series 700, HP-UX 9.09), or PHNE_5388 (series 700, HP-UX 9.09+), or PHNE_5389 (series 800, HP-UX 9.08) AVAILABILITY: All patches are available now. _______________________________________________________________________ I. Vulnerability in /usr/lib/sendmail A. A vulnerability in sendmail A vulnerability in sendmail has been discovered that permits remote users to cause sendmail to execute any program that is allowed with the permissions: uid=1(daemon) gid=1(other) Files and programs that are not world-writeable or world-executable and are not in the 'other' group or owned by 'daemon' are safe from modification. This means that /etc/passwd cannot be modified, for example. B. Fixing the problems The two vulnerabilities can be eliminated from releases 8.x and 9.x of HP-UX by applying a patch. Hewlett-Packard recommends that all customers concerned with the security of their HP-UX systems apply the appropriate patch as soon as possible. It is further advised that system administrators closely scan their mail syslogs for evidence of any unusual activity, using: grep "|" /usr/spool/mqueue/syslog* [Editor's note: If your site links grep to egrep or the Gnu grep, the above command matches every line in the file. An alternative is to use fgrep where you are looking for the "|" character. -- CERT CC] If there is any evidence of an intrusion, system administrators are strongly urged to require password changes for all accounts. C. How to Install the Patch (for HP-UX 8.x and 9.x) 1. Determine which patch is appropriate for your hardware platform and operating system: PHNE_5402 (series 700/800, HP-UX 9.x), PHNE_5401 (series 700/800, HP-UX 8.x), PHNE_5384 (series 300/400, HP-UX 9.x), PHNE_5383 (series 300/400, HP-UX 8.x), PHNE_5387 (series 700, HP-UX 9.09), PHNE_5388 (series 700, HP-UX 9.09+), PHNE_5389 (series 800, HP-UX 9.08) 2. Hewlett Packard's HP-UX patches are available via email and the World Wide Web. To obtain a copy of the HP SupportLine email service user's guide, send the following in the TEXT PORTION OF THE MESSAGE to email@example.com (no Subject is required): send guide The users guide explains the process for downloading HP-UX patches via email and other services available. World Wide Web service for downloading of patches is available via our URL: http://support.mayfield.hp.com 3. Apply the patch to your HP-UX system. 4. Examine /tmp/update.log for any relevant WARNINGs or ERRORs. This can be done as follows: a. At the shell prompt, type "tail -60 /tmp/update.log | more" b. Page through the next three screens via the space bar, looking for WARNING or ERROR messages. D. Impact of the patch and workaround The patch for HP-UX releases 8.x and 9.x provides a new version of /usr/lib/sendmail which fixes the vulnerability. No patches will be available for versions of HP-UX prior to 8.0. E. To subscribe to automatically receive future NEW HP Security Bulletins from the HP SupportLine mail service via electronic mail, send an email message to: firstname.lastname@example.org (no Subject is required) Multiple instructions are allowed in the TEXT PORTION OF THE MESSAGE, here are some basic instructions you may want to use: To add your name to the subscription list for new security bulletins, send the following in the TEXT PORTION OF THE MESSAGE: subscribe security_info To retrieve the index of all HP Security Bulletins issued to date, send the following in the TEXT PORTION OF THE MESSAGE: send security_info_list To get a patch matrix of current HP-UX and BLS security patches referenced by either Security Bulletin or Platform/OS, put the following in the text portion of your message: send hp-ux_patch_matrix World Wide Web service for browsing of bulletins is available via our URL: http://support.mayfield.hp.com Choose "Support news", then under Support news, choose "Security Bulletins" F. To report new security vulnerabilities, send email to email@example.com _______________________________________________________________________ =========================FORWARDED TEXT ENDS HERE============================= CERT bulletins, CERT advisories, information about FIRST representatives, and other information related to computer security are available for anonymous FTP from info.cert.org. CERT advisories and bulletins are also posted on the USENET newsgroup comp.security.announce. If you would like to have future advisories and bulletins mailed to you or to a mail exploder at your site, please send mail to firstname.lastname@example.org. If you wish to send sensitive incident or vulnerability information to CERT staff by electronic mail, we strongly advise that the e-mail be encrypted. The CERT Coordination Center can support a shared DES key, PGP (public key available via anonymous FTP on info.cert.org), or PEM (contact CERT staff for details). Internet E-mail: email@example.com Telephone: +1 412-268-7090 (24-hour hotline) CERT personnel answer 8:30 a.m.-5:00 p.m. EST(GMT-5)/EDT(GMT-4), and are on call for emergencies during other hours. Fax: +1 412-268-6989 CERT Coordination Center Software Engineering Institute Carnegie Mellon University Pittsburgh, PA 15213-3890 USA CERT is a service mark of Carnegie Mellon University.