_____________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ _____________________________________________________ INFORMATION BULLETIN Majordomo distribution list administrator vulnerabilities June 15, 1994 1400 PDT Number E-30 ______________________________________________________________________________ PROBLEM: Two vulnerabilities in Majordomo distribution list administrator. PLATFORMS: All unix systems using Majordomo versions 1.91 and earlier. DAMAGE: Remote users may gain access to the Majordomo account. SOLUTION: Upgrade to Majordomo 1.92 or apply quick fix described below. ______________________________________________________________________________ VULNERABILITY This vulnerability is being discussed on public mailing lists ASSESSMENT: and is currently being exploited. CIAC recommends that sites determine if they are using Majordomo for their distribution lists, and, if so, follow the steps described below. ______________________________________________________________________________ Critical Information about the Majordomo distribution list administrator vulnerabilities CIAC has learned of two vulnerabilities in the Majordomo distribution list administrator software. These allow intruders to gain remote access to the Majordomo account and execute arbitrary commands. Exploitation does not require a valid username/password combination and bypasses firewalls and TCP wrappers. This vulnerability affects all versions of Majordomo up to and including version 1.91. It does not affect users of Majordomo (i.e., subscribers), nor hosts using other distribution list managers. CIAC recommends that sites determine if they are running Majordomo. If so, upgrade to version 1.92. If the associated mailer is sendmail and upgrading immediately is not possible, then, as an interim solution, follow the instructions for the quick fix in 2 below. 1. Upgrading to Majordomo 1.92 Obtain Majordomo 1.92 via anonymous ftp in the indicated directory on any one of the following servers: ftp.pgh.net:/pub/majordomo/majordomo-1.92.tar.Z ftp.cs.umb.edu:/pub/rouilj/majordomo-1.92.tar.Z FTP.GreatCircle.COM:/pub/majordomo/majordomo-1.92.tar.Z Follow the installation instructions in the included main README file. Note that the compressed file should have the following checksum and signature. BSD SVR4 File Checksum Checksum MD5 Digital Signature ____________________ _________ _________ ________________________________ majordomo-1.92.tar.Z 55701 223 23408 446 17d9bb9fd4872ab09d01bfeb643b5ebb If your copy computes differently, contact the ftp site or CIAC before proceeding. 2. Quick fix for versions 1.91 and earlier that use the sendmail mailer (this fix is not supported for other mailers). For version 1.91, perform the first step only. For version 1.90 and earlier, perform both steps. Versions 1.91 and earlier: Disable new-list by either renaming or removing it from the aliases file. Versions 1.90 and earlier: Find all occurrences of strings of any the following forms: "|/usr/lib/sendmail -f $to" #majordomo.pl "|/usr/lib/sendmail -f $reply_to" #request-answer "|/usr/lib/sendmail -f $reply_to $list-approval" # new-list "|/usr/lib/sendmail -f \$to" #majordomo.cf Change all occurrences of that string to "|/usr/lib/sendmail -f -t" You should find these strings in the request-answer, majordomo.pl, and your local majordomo.cf files. ______________________________________________________________________________ CIAC acknowledges the CERT Coordination Center and John Rouillard of the University of Massachusetts at Boston for providing the information for this bulletin. ______________________________________________________________________________ For additional information or assistance, please contact CIAC: Voice: 510-422-8193 FAX: 510-423-8002 STU-III: 510-423-2604 E-mail: ciac@llnl.gov CIAC has several self-subscribing mailing lists for electronic publications: 1. 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