Updated:  October 04, 2001

Status

Affected

Vendor Statement

IBM Global Services Managed Security Services Outside Advisory Redistribution 11 SEP 2001 0:53 GMT MSS-OAR-E01-2001:391.1 The MSS Outside Advisory Redistribution is designed to provide customers of IBM Managed Security Services with access to the security advisories sent out by other computer security incident response teams, vendors, and other groups concerned about security. IBM makes no representations and assumes no responsibility for the contents or accuracy of the advisories themselves. IBM MSS is forwarding the following information from . Contact information for is included in the forwarded text below. Please contact them if you have any questions or need further information. ----------- Forwarded Information Starts Here. -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 IBM SECURITY ADVISORY Fri Sep 7 11:18:24 CDT 2001 VULNERABILITY SUMMARY VULNERABILITY: Buffer Overflow Vulnerabilities in lpd PLATFORMS: IBM AIX 4.3 and 5.1 SOLUTION: Apply the emergency-fixes described below. THREAT: Malicious user could obtain root privileges, or cause a denial of service (DoS). CERT Advisory: See CERT CA-2001-15 for info on Solaris vulnerability. Also see the posting, http://xforce.iss.net/alerts/advise94.php, at the Internet Security Systems site for info on BSD implementations of lpd. CVE Candidate: CAN-2001-0670 CAN-2001-0671 DETAILED INFORMATION I. Description The Line Printer daemon, lpd, shipped with AIX contains several buffer overflow vulnerabilities that potentially allow a malicious remote user to gain root privileges. Two of the three vulnerabilities found require the attacker's system be listed in /etc/hosts.lpd or /etc/hosts.equiv. The third requires that the malicious user have control over the victim's domain name server (DNS). II. Impact A malicious local or remote user can use a well-crafted exploit code to gain root privileges on the attacked system, compromising the integrity of the system and its attached local network. If the malicious user is unable to gain root access, he or she could still cause a system crash (DoS) via this vulnerability. III. Solutions A. Official fix IBM is working on the following fixes which will be available soon: AIX 4.3: APAR #IY23037 AIX 5.1: APAR #IY23041 NOTE: Fix will not be provided for versions prior to 4.3 as these are no longer supported by IBM. Affected customers are urged to upgrade to 4.3.3 at the latest maintenance level, or to 5.1, when it becomes available. B. How to minimize the vulnerability WORKAROUND None recommended. IBM advises customers to disable the line printer daemon until an efix or official APAR is installed. In general, customers are advised to disable all unused daemon services as good security practice. EMERGENCY FIX (efix): Temporary fixes for AIX 4.3.x and 5.1 systems are available. The temporary fixes can be downloaded via ftp from: ftp://aix.software.ibm.com/aix/efixes/security/lpd_efix.tar.Z The efix tarball consists of two patched lpd binaries, one for AIX 4.3.x systems (lpd.43) and one for AIX 5.1 (scheduled for release soon; binary is lpd.51). A copy of this Advisory is also included. These temporary fixes have not been fully regression tested; thus, IBM does not warrant the fully correct functioning of the efix. Customers install the efix and operate the modified version of AIX at their own risk. To proceed with efix installation: First, verify the MD5 cryptographic hash sums of each efix files you obtain from unpacking the efix tarball with those given below. These should match exactly; if they do not, double check the hash results and the download site address. If OK, contact IBM AIX Security at security-alert@austin.ibm.com and describe the discrepancy. Filename sum md5 lpd.43X.tar 11225 20 3c7e6f0ef29b6147835213253de8f1bf lpd.51B.tar 35507 80 38bc7f7516d76b8a89914fdab97e1377 Efix Installation Instructions: 1. Become root, if not already done. 2. In a scratch or tmp directory, uncompress and untar the efix: a. uncompress lpd_efix.tar.Z b. tar -xvf lpd_efix.tar 3. If you are running an AIX 4.3.x system, copy the lpd.43 file to /usr/sbin. Do the same if you have AIX 5.1 running, except copy the lpd.51 file. 4. Stop the lpd daemon if it is currently running: a. stopsrc -s lpd 5. Make a backup copy of the existing lpd binary package in case something goes wrong with the installation of the efix: a. cp /usr/sbin/lpd /usr/sbin/lpd.original 6. Now copy the efix binary to take the place of the original lpd: a. cp /usr/sbin/lpd.43 (or lpd.51, as appropriate) /usr/sbin/lpd. 7. Check to be certain that the new lpd is executable by root and is assigned proper permissions otherwise. 8. Restart the lpd daemon: a. startsrc -s lpd IV. Obtaining Fixes IBM AIX APARs may be ordered using Electronic Fix Distribution (via the FixDist program), or from the IBM Support Center. For more information on FixDist, and to obtain fixes via the Internet, please reference http://techsupport.services.ibm.com/rs6k/fixes.html or send email to "aixserv@austin.ibm.com" with the word "FixDist" in the "Subject:" line. To facilitate ease of ordering all security related APARs for each AIX release, security fixes are periodically bundled into a cumulative APAR. For more information on these cumulative APARs including last update and list of individual fixes, send email to "aixserv@austin.ibm.com" with the word "subscribe Security_APARs" in the "Subject:" line. V. Acknowledgements Many thanks to Internet Security Services (ISS) for identifying these vulnerabilities in lpd, and to the CERT/CC for preparing and distributing the Vulnerability Notes provided to us vendors. VI. Contact Information Comments regarding the content of this announcement can be directed to: security-alert@austin.ibm.com To request the PGP public key that can be used to encrypt new AIX security vulnerabilities, send email to security-alert@austin.ibm.com with a subject of "get key". If you would like to subscribe to the AIX security newsletter, send a note to aixserv@austin.ibm.com with a subject of "subscribe Security". To cancel your subscription, use a subject of "unsubscribe Security". To see a list of other available subscriptions, use a subject of "help". IBM and AIX are a registered trademark of International Business Machines Corporation. All other trademarks are property of their respective holders. -----BEGIN PGP SIGNATURE----- Version: PGP Personal Privacy 6.5.3 iQA/AwUBO51SPcXrSKQHhgFwEQLSAQCglnEAvxiWRujJvjLTc1C4W6Gu1OEAoNAJ v5NsLwb8f7D/EkUSjvjRS9Qj =HoWQ -----END PGP SIGNATURE----- ----------- Forwarded Information Ends Here. 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Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.

Addendum

The CERT/CC has no additional comments at this time.