============================================================================= CA-94:12 CERT Advisory July 14, 1994 Sendmail Vulnerabilities ----------------------------------------------------------------------------- This advisory supersedes all previous CERT advisories about sendmail(8) for the vendors listed below. There are two vulnerabilities in some vendors' versions of sendmail(8). One, in the debug option, enables local users to gain root access. The other, in the error message header option, enables local users to read any file on the system. Both vulnerabilities are known in the intruder community. The CERT Coordination Center is in contact with vendors concerning these vulnerabilities. Those who have patches available are listed at the end of this advisory. If your vendor's name is not on the list, contact the vendor directly for information on whether their version of sendmail(8) is vulnerable and, if so, whether a patch is available. The list of vendors and patches is reproduced in "CA-94:12.README" file. As we receive additional information relating to this advisory, we will place it, along with any clarifications, in the README file. CERT advisories and their associated README files are available by anonymous FTP from info.cert.org. We encourage you to check the README files regularly for updates on advisories that relate to your site. ----------------------------------------------------------------------------- I. Description There is a problem with the debug option (-d) and/or the error message header option (-oE) in some vendors' versions of sendmail(8). An exploitation script has been circulated for sendmail -d, and intruders are actively exploiting this vulnerability. As of the date of this advisory, we have not received reports of the sendmail -oE vulnerability being exploited. II. Impact The sendmail -d vulnerability allows local users to gain root access. The sendmail -oE vulnerability allows local users to read any file on the system. III. Solution Obtain and install the appropriate patch according to the instructions included with the patch. Below is a summary of the vendors listed in the current version of the CA-94:12.README file, and the status they have provided. More complete information, including how to obtain patches, is provided in the appendix of this advisory and reproduced in the README file associated with this advisory. We will update the README file as we receive more information from vendors. Vendor or Source Status ---------------- ------------ Eric Allman Versions 8.6.8 and 8.6.9 are available and not vulnerable Amdahl Not vulnerable Apple Patch available Berkeley Software Design Patch available Convex OS 11.0 not vulnerable; patch available for 10.x Data General Patch available Digital Equipment Patch available Hewlett Packard Patch available IBM Patch available Open Software Foundation Patch available Santa Cruz Operation Patch in progress Sun Patch available Note: Some sites may find it feasible to install Eric Allman's sendmail 8.6.9, which is in the public domain (see the appendix for details). However, depending upon the currently installed sendmail program, switching to a different sendmail may require significant effort. The site administrator may need to become familiar with the new program, and the site's sendmail configuration file may require considerable modification in order to provide existing functionality. In some cases, the configuration file of the site's sendmail may be incompatible with that of sendmail 8.6.9. --------------------------------------------------------------------------- The CERT Coordination Center wishes to thank all the vendors listed in this advisory for their efforts in responding to this problem. --------------------------------------------------------------------------- If you believe that your system has been compromised, contact the CERT Coordination Center or your representative in Forum of Incident Response and Security Teams (FIRST). If you wish to send sensitive incident or vulnerability information to CERT via electronic mail, CERT strongly advises that the e-mail be encrypted. CERT can support a shared DES key, PGP (public key available via anonymous FTP on info.cert.org), or PEM (contact CERT for details). Internet E-mail: cert@cert.org Telephone: 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. CERT Coordination Center Software Engineering Institute Carnegie Mellon University Pittsburgh, PA 15213-3890 USA Past advisories and their related README files, information about FIRST representatives, and other information related to computer security are available for anonymous FTP from info.cert.org. ...................................................................... Appendix: Vendor Information Current as of July 14, 1994 See CA-94:12.README for updated information; this file supersedes CA-93:16a.README. Below is information we have received from vendors who have patches available or upcoming for the vulnerabilities described in this advisory, as well as vendors who have confirmed that their products are not vulnerable. If your vendor's name is not in one of these lists, contact the vendor directly for information on whether their version of sendmail is vulnerable and, if so, the status of patches to address the vulnerabilities. --------------------------------------- Eric Allman Sendmail versions 8.6.8 and 8.6.9 are not vulnerable. The problem with -d was fixed in sendmail 8.6.7, and -oE was fixed in sendmail 8.6.8. Even if you are running 8.6.8, you may want to upgrade to 8.6.9 for the additional features. Version 8.6.9 is available by anonymous FTP from ftp.cs.berkeley.edu in the directory ucb/sendmail. MD5 (sendmail.8.6.9.base.tar.Z) = 9bffb19116e7fdbb6ec56ccf9344895b MD5 (sendmail.8.6.9.cf.tar.Z) = 37ecb776ec61f596d01fbb46bae6e72f MD5 (sendmail.8.6.9.misc.tar.Z) = e083dbd609bdaf4b46c52f2546b3d1e5 MD5 (sendmail.8.6.9.xdoc.tar.Z) = 0df46586fbe767bf7060068331de7186 --------------------------------------- Amdahl All versions of UTS 2.1 use smail rather than sendmail and are not vulnerable to these problems. --------------------------------------- Apple Computer, Inc. A patch to version 3.1 of A/UX for these vulnerabilities is available by anonymous FTP from ftp.support.apple.com or aux.support.apple.com; in each case, a compressed, replacement version (8.6.4.1) of sendmail is in pub/aux.patches. Filename sendmail.Z BSD checksum 02992 182 SysV checksum 10129 364 MD5 checksum df4ca82f624ee8f4404c5e979e7e3d24 Uncompress this file using compress(1) and replace the previous version (8.6.4) in /usr/lib; be sure to kill the running sendmail and restart. Earlier versions of A/UX are not supported by this patch. Users of previous versions are encouraged by Apple to update their system to A/UX 3.1 or compile and install the version of sendmail available from ftp.cs.berkeley.edu. Customers should contact their reseller for any additional information. --------------------------------------- Berkeley Software Design (BSDI) Patches to sendmail for these problems in BSD/386 V1.1 are available from BSDI customer support: BSDI Customer Support Berkeley Software Design, Inc. 7759 Delmonico Drive Colorado Springs, CO 80919 Toll Free: +1 800 ITS BSD8 (+1 800 486 2738) Phone: +1 719 260 8114 Fax: +1 719 598 4238 Email: support@bsdi.com --------------------------------------- Convex ConvexOS 11.0 (the most recent production OS) does not contain the vulnerabilities. Convex customers running ConvexOS 10.x should install the CONVEX TAC PATCH 10.3.129, which is the full ConvexOS 11.0 mail system back ported to ConvexOS 10.x. The 10.3.129 README file is reproduced below: The following patch information is provided by a member of the CONVEX TAC. There is no express or implied warranty. The maintenance of this patch is the responsibility of the installer. The existence of this patch does not guarantee that the patch or its functionality will be available in the next release of the product. PATCH PRODUCT NAME: ConvexOS Mail System PATCH FOR VERSION NUMBER: 10.3 PATCH MODULE NAME: /usr/lib/sendmail NEW VERSION NUMBER OF PRODUCT: 10.3.129 RELATED BUG REPORTS: X-33414, X-33531 PATCH INSTALLATION: Pre-installation precautions: if from tape: %tpmount %installsw -i NOTE: If installing from tape, you must use a no-rewind tape device, such as /dev/rmt20 or /dev/rdat0n, /dev/eb0nr, or /dev/rtc0n. if from script: % ./Script.sh The Convex Technical Assistance Center is available for additional information at 800-952-0379. --------------------------------------- Data General Corporation DG/UX systems are not at risk from the -oE problem. Patches will be made available for all supported releases of DG/UX for the -d problem and it will be fixed in future releases of DG/UX starting with DG/UX 5.4 Release 3.10. Affected sites should call their Customer Support Center for information regarding this patch. --------------------------------------- Digital Equipment Corporation [The following information was excerpted from DEC SECURITY ADVISORY #0505. Please contact DEC for a complete copy of that advisory.] Products Affected: ULTRIX Versions 4.3, 4.3A, V4.4 DECnet-ULTRIX Version 4.2 DEC OSF/1 Versions 1.2, 1.3, 1.3A, 2.0 SOLUTION: ULTRIX: Upgrade/Install ULTRIX to an minimum of V4.4 and install the Security Enhanced Kit DEC OSF/1: Upgrade/Install to a minimum of V1.2 and install the Security Enhanced Kit Please refer to the applicable Release Note information prior to upgrading your installation. These kits are available from Digital Equipment Corporation by contacting your normal Digital support channel or by request via DSNlink for electronic transfer. KIT PART NUMBERS and DESCRIPTIONS CSCPAT_4060 V1.0 ULTRIX V4.3 thru V4.4 (Includes DECnet-ULTRIX V4.2) CSCPAT_4061 V1.0 DEC OSF/1 V1.2 thru V2.0 _______________________________________________________________ These kits will not install on versions previous to ULTRIX V4.3 or DEC OSF/1 V1.2. _______________________________________________________________ Digital urges you to periodically review your system management and security procedures. Digital will continue to review and enhance the security features of its products and work with customers to maintain and improve the security and integrity of their systems. NOTE: For non-contract/non-warranty customers contact your local Digital support channels for information regarding these kits. --------------------------------------- Hewlett-Packard HP/UX does not support the -oE option. To fix the -d problem, obtain patch PHNE_4533 from Hewlett-Packard. This patch may be obtained from HP via FTP (this is NOT anonymous FTP) or the HP SupportLine. To obtain HP security patches, you must first register with the HP SupportLine. The registration instructions are available by anonymous FTP from info.cert.org in the file "pub/vendors/hp/supportline_and_patch_retrieval". --------------------------------------- IBM A patch for the -d vulnerability can be ordered from IBM as APAR IX44020 (PTF U431041). AIX is not vulnerable to the -oE problem. To order APARs from IBM in the U.S., call 1-800-237-5511 and ask that it be shipped to you as soon as it is available. To obtain APARs outside of the U.S., contact your local IBM representative. --------------------------------------- Open Software Foundation (OSF) For OSF/1 R1.3: CR11057 describes how to fix the -d option problem in the sources. OSF/1 is not vulnerable to the -oE problem. --------------------------------------- The Santa Cruz Operation, Inc. (SCO) SCO systems are not affected by the -oE problem and a patch for the -d problem on the following platforms will soon be available: SCO TCP/IP Release 1.2.0 for SCO XENIX SCO TCP/IP Release 1.2.1 for SCO UNIX SCO Open Desktop Release 3.0 SCO Open Desktop Lite Release 3.0 SCO Open Server Network System, Release 3.0 SCO Open Server Enterprise System, Release 3.0 For more information contact SCO at: Electronic mail: support@sco.COM The Americas, Pacific Rim, Asia, and Latin America: 6am-5pm Pacific Daylight Time (PDT) --------------------------------------------------- 1-408-425-4726 (voice) 1-408-427-5443 (fax) Europe, Middle East, Africa: 9am-5:30pm British Daylight Time (BST) +44 (0)923 816344 (voice) +44 (0)923 817781 (fax) --------------------------------------- Sun Microsystems, Inc. A. Patch list Sun has produced patches against these vulnerabilities for the versions of SunOS shown below. 4.1.1 100377-15 4.1.2 100377-15 4.1.3 100377-15 4.1.3_U1 101665-02 5.1_x86 101352-03 (Solaris x86) 5.1 100834-11 (Solaris 2.1) 5.2 100999-59 (Solaris 2.2) 5.3 101318-41 (Solaris 2.3) B. Patch notes 1. The last security-related patch for 4.1.x sendmail was distributed as 100377-08 (announced 23 December 1993). Revisions -09 through -14 were not related to security. 2. The 4.1.1 patch includes a version built for the sun3 architecture. 3. The 4.1.3 version of the patch is also applicable to 4.1.3C systems. 4. The patch listed for 4.1.3_U1 (Solaris 1.1.1) applies to both the A and B versions. This is currently true for all U1 patches. 5. One of the listed patches (100834-11, for SunOS 5.1) is actually a jumbo kernel patch into which sendmail was bundled. The other two SunOS 5.x patches, and all of the 4.1.x patches, contain only sendmail fixes. (Sun bundled all 5.x sendmails into jumbo kernel patches earlier this year, but later unbundled the 5.3 and 5.2 patches in response to customer complaints. The 5.1 sendmail will be unbundled as well later this summer. 6. Sun releases new patch versions frequently. For this reason, when requesting patches you should ask for the specified "or later" version, e.g., "version 11 or later of patch 100834". Patches can be obtained from local Sun Answer Centers and Sunsolve. U.S. users can contact Sun a 800-USA-4SUN. Sun can also be reached by e-mail at security-alert@sun.com. ---------------------------------------