============================================================================= CA-93:01 CERT Advisory January 13, 1993 Revised Hewlett-Packard NIS ypbind Vulnerability ----------------------------------------------------------------------------- *** THIS IS A REVISED CERT ADVISORY *** *** IT CONTAINS NEW INFORMATION REGARDING AVAILABILITY OF IMAGE KITS *** *** SUPERSEDES CERT ADVISORY CA-92:17 *** The CERT Coordination Center has received information concerning a vulnerability in the NIS ypbind module for the Hewlett-Packard (HP) HP/UX Operating System for series 300, 700, and 800 computers. HP has provided revised patches for all of the HP/UX level 8 releases (8.0, 8.02, 8.06, and 8.07). This problem is fixed in HP/UX 9.0. The following patches have been superseded: Patch ID Replaced by Patch ID PHNE_1359 PHNE_1706 PHNE_1360 PHNE_1707 PHNE_1361 PHNE_1708 All HP NIS clients and servers running ypbind should obtain and install the patch appropriate for their machine's architecture as described below. ----------------------------------------------------------------------------- I. Description A vulnerability in HP NIS allows unauthorized access to NIS data. II. Impact Root on a remote host running any vendor's implementation of NIS can gain root access on any local host running HP's NIS ypbind. Local users of a host running HP's NIS ypbind can also gain root access. III. Solution 1) All HP NIS clients and servers running ypbind should obtain and install the patch appropriate for their machine's architecture. These patches contain a version of ypbind that only accepts ypset requests from a superuser port on the local host. This prevents a non-superuser program from sending rogue ypset requests to ypbind. They also include the mod from the superseded patches which prevented a superuser on a remote system from issuing a ypset -h command to the local system and binding the system to a rogue ypserver. These patches 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 via anonymous FTP at cert.org (192.88.209.5) in the file "pub/vendors/hp/supportline_and_patch_retrieval". The new patch files are: Architecture Patch ID Filename Checksum ------------ -------- -------- -------- Series 300 PHNE_1706 /hp-ux_patches/s300_400/8.X/PHNE_1706 38955 212 Series 700 PHNE_1707 /hp-ux_patches/s700/8.X/PHNE_1707 815 311 Series 800 PHNE_1708 /hp-ux_patches/s800/8.X/PHNE_1708 56971 299 2) The instructions for installing the patch are provided in the PHNE_xxxx.text file (this file is created after the patch has been unpacked). The checksums listed above are for the patch archive files from HP. Once unpacked, each shell archive contains additional checksum information in the file "patchfilename.text". This checksum is applicable to the binary patch file "patchfilename.updt". If you have any questions about obtaining or installing the patches, contact the USA HP SupportLine at 415-691-3888, or your local HP SupportLine number. Please note that the telephone numbers in this advisory are appropriate for the USA and Canada. ----------------------------------------------------------------------------- The CERT Coordination Center wishes to thank Brian Kelley of Ford Motor Company for bringing this vulnerability to our attention. We would also like to thank Hewlett-Packard for their response to this problem. ----------------------------------------------------------------------------- If you believe that your system has been compromised, contact the CERT Coordination Center or your representative in FIRST (Forum of Incident Response and Security Teams). Internet E-mail: cert@cert.org Telephone: 412-268-7090 (24-hour hotline) CERT personnel answer 7:30 a.m.-6:00 p.m. EST(GMT-5)/EDT(GMT-4), on call for emergencies during other hours. CERT Coordination Center Software Engineering Institute Carnegie Mellon University Pittsburgh, PA 15213-3890 Past advisories, information about FIRST representatives, and other information related to computer security are available for anonymous FTP from cert.org (192.88.209.5).