-----BEGIN PGP SIGNED MESSAGE----- [ For Public Release ] __________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN INN News Server Vulnerabilities July 22, 1997 20:00 GMT Number H-85 ______________________________________________________________________________ PROBLEM: A number of vulnerabilities have been identified in the INN News Server. PLATFORM: All platforms running of INN prior to version 1.6. DAMAGE: May allow remote individuals to obtain access to vulnerable systems. However, post access is required to exploit these vulnerabilities. SOLUTION: Upgrade to INN version 1.6 immediately. ______________________________________________________________________________ VULNERABILITY Exploit details involving this vulnerability have been made ASSESSMENT: publicly available. ______________________________________________________________________________ [ Start Secure Networks Inc. Advisory ] Secure Networks Inc. Security Advisory July 21, 1997 INN news server vulnerabilities This advisory addresses a number of vulnerabilities present in all versions of INN prior to version 1.6. Problem Description: A number of vulnerabilities exist in all versions of INN prior to version 1.6 which allow remote individuals to obtain access to vulnerable systems. Post access is required to exploit these vulnerabilities. However, due to the method with which news is propagated, once a single server has been broken into, all of its peers can be accessed. Technical Details: A number of string copies within the INN news server fail to check the size of data they are copying. This results in buffer overflows in several locations, allowing individuals to execute commands remotely, including spawning a shell on the NNTP port. An example of this situation is in the processing of the "From: " line by the nnrpd process. In the ARTpost function in post.c, the From: line is copied into a buffer on the stack without performing bounds checking: STRING ARTpost(article, idbuff) ... char buff[NNTP_STRLEN + 2], frombuf[SMBUF]; ... strcpy(frombuf, HDR(_from)); ... By crafting appropriate arguments in the From: header of the message, an attacker can cause nnrpd to overwrite its stack, overwrite the function return pointer on the stack, and thus execute arbitrary binary code. Vulnerable Operating Systems and Software All versions of INN prior to version 1.6 are vulnerable. To determine which version of INN you are running, issue the following command on your news server: % telnet localhost 119 Your NNTP server version string will be displayed. A typical output from a vulnerable NNTP server would read: Trying 127.0.0.1... Connected to localhost. Escape character is '^]'. 200 freebsd.secnet.com InterNetNews NNRP server INN 1.5.1 17-Dec-1996 ready A line reading: telnet: Unable to connect to remote host: Connection refused means that you are not running an NNTP server. Fix Information INN version 1.6 has been made availible at ftp://ftp.isc.org/isc/inn. A fix will not be made availible for prior releases and it is suggested that all users running INN upgrade to version 1.6 immediately. Please note that INN version 1.6 is currently in beta testing stages, therefore new versions may appear at this location in the future. Additional Information Secure Networks Inc. wishes to thanks James Brister for his assistance in this advisory and a resolution to these problems. You can contact Secure Networks Inc. at using the following PGP key: Type Bits/KeyID Date User ID pub 1024/9E55000D 1997/01/13 Secure Networks Inc. Secure Networks - -----BEGIN PGP PUBLIC KEY BLOCK----- Version: 2.6.3ia mQCNAzLaFzIAAAEEAKsVzPR7Y6oFN5VPE/Rp6Sm82oE0y6Mkuof8QzERV6taihn5 uySb31UeNJ4l6Ud9alOPT/0YdeOO9on6eD1iU8qumFxzO3TLm8nTAdZehQSAQfoa rWmpwj7KpXN/3n+VyBWvhpBdKxe08SQN4ZjvV5HXy4YIrE5bTbgIhFKeVQANAAUR tCVTZWN1cmUgTmV0d29ya3MgSW5jLiA8c25pQHNlY25ldC5jb20+iQCVAwUQM1yd EB/bLKAOe7p9AQFptAQAiYpaZCpSmGgr05E698Z3t5r5BPAKUEtgvF53AvZUQLxz ZsYsVU5l5De0qKWJOQ/9LiDyWu1lvKhlTphbLy2RatWD4kO3oQL9v3TpSXm2WQhU uIzyZvj7S5ENodNnKn+gCDIvbou6OMot+7dRbWWgN2oabbru4CSlOxbG++yaTz+J AJUDBRAzTefbtOXez5VgyLkBAd0bA/43eGEgvPOFK+HHWCPpkSWCwtrtDU/dxOVz 9erHnT/CRxeojCI+50f71Qe+kvx9Q1odz2Jl/fLxhnPQdbPnpWblIbu4F8H+Syrj HTilDrl1DWa/nUNgK8sb27SMviELczP1a8gwA1eo5SUCG5TWLLTAzjWOgTxod2Ha OwseUHmqVIkAlQMFEDNOVsr/d6Iw8NVIbQEBxM0D/14XRfgSLwszgJcVbslMHm/B fF6tHoWYojzQle3opOuMYHNN8GsMZRkc1qQ8QuNA9Aj5+qDqEontGjV5IvhBu1fY FM77AhagskaFCZxwqV64Qrk328WDO89NGSd+RuovVNruDdn20TxNCEVuPTHjI0UA 8H+E6FW9jexg6RTHhPXYtCVTZWN1cmUgTmV0d29ya3MgPHNlY3VyaXR5QHNlY25l dC5jb20+iQCVAwUQMtqTKB/bLKAOe7p9AQFw5wQAgUwqJ+ZqfEy/lO1srU3nzxLA X0uHGHrMptRy/LFo8swD6G1TtWExUc3Yv/6g2/YK09b5WmplEJ+Q09maQIw+RU/s cIY+EsPauqIq4JTGh/Nm0Z4UDl2Y1x4GNtm0YqezxUPS0P0A3LHVLJ3Uo5og0G8O gPNrfbVz5ieT14OSCWCJAJUDBRAy2hd2/3eiMPDVSG0BAVNhBACfupfAcNhhnQaq aI03DOOiZSRjvql1xw4V+pPhM+IksdSK3YNUZVJJtANacgDhBT+jAPRaYbBWI3A5 ZMdcSNM8aTG0LWMLIOiOYEm6Lgd3idRBFN0Js08eyITl8mhZ33mDe4I0KQri9UiV ZcPYTbb9CWM6Hv2cMbt6S6kLnFziqIkAlQMFEDLaF0+4CIRSnlUADQEBCLoEAJwt UofDgvyZ4nCDx1KKAPkkXBRaPMWBp46xeTVcxaYiloZfwHfpk1h2mEJAxmAsvizl OtIppHl4isUxcGi/E2mLCLMvis22/IQP/9obPahPvgNaMLVtZljO1Nv3QFEkNciL FEUTNJHR1ko7ibCxkBs4cOpirFuvTMDvWnNaXAf8 =DchE - -----END PGP PUBLIC KEY BLOCK----- You can find past Secure Networks advisories at http://www.secnet.com/advisories or at ftp://ftp.secnet.com/pub/advisories You can browse our web site at http://www.secnet.com You can subscribe to our security advisory mailing list by sending mail to majordomo@secnet.com with the line "subscribe sni-advisories" Copyright Notice The contents of this advisory are Copyright (C) 1997 Secure Networks Inc, and may be distributed freely provided that no fee is charged for distribution, and that proper credit is given. [ End Secure Networks Inc. Advisory ] CIAC wishes to acknowledge the contributions of Secure Networks Inc. for the information contained in this bulletin. CIAC, the Computer Incident Advisory Capability, is the computer security incident response team for the U.S. Department of Energy (DOE) and the emergency backup response team for the National Institutes of Health (NIH). CIAC is located at the Lawrence Livermore National Laboratory in Livermore, California. CIAC is also a founding member of FIRST, the Forum of Incident Response and Security Teams, a global organization established to foster cooperation and coordination among computer security teams worldwide. CIAC services are available to DOE, DOE contractors, and the NIH. CIAC can be contacted at: Voice: +1 510-422-8193 FAX: +1 510-423-8002 STU-III: +1 510-423-2604 E-mail: ciac@llnl.gov For emergencies and off-hour assistance, DOE, DOE contractor sites, and the NIH may contact CIAC 24-hours a day. During off hours (5PM - 8AM PST), call the CIAC voice number 510-422-8193 and leave a message, or call 800-759-7243 (800-SKY-PAGE) to send a Sky Page. CIAC has two Sky Page PIN numbers, the primary PIN number, 8550070, is for the CIAC duty person, and the secondary PIN number, 8550074 is for the CIAC Project Leader. Previous CIAC notices, anti-virus software, and other information are available from the CIAC Computer Security Archive. World Wide Web: http://ciac.llnl.gov/ Anonymous FTP: ciac.llnl.gov (198.128.39.53) Modem access: +1 (510) 423-4753 (28.8K baud) +1 (510) 423-3331 (28.8K baud) CIAC has several self-subscribing mailing lists for electronic publications: 1. CIAC-BULLETIN for Advisories, highest priority - time critical information and Bulletins, important computer security information; 2. CIAC-NOTES for Notes, a collection of computer security articles; 3. 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LAST 10 CIAC BULLETINS ISSUED (Previous bulletins available from CIAC) H-76: Netscape Navigator Security Vulnerability H-77: Microsoft IIS Boundary Condition Vulnerability H-78: ICMP vulnerability in Windows 95 and NT 4.0 H-79: Vellum 3D CD-ROM contains Mac MBDF Virus H-80: SGI IRIX xlock Vulnerability H-42a: HP MPE/iX with ICMP Echo Request (ping) Vulnerability H-81: HP-UX swinstall command in SD-UX Vulnerability H-82: Lynx Temporary Files & Downloading Vulnerabilities H-83: Solaris ping Vulnerability H-84: Windows NT NtOpenProcessToken Vulnerability -----BEGIN PGP SIGNATURE----- Version: 4.0 Business Edition iQCVAwUBM9Yj6rnzJzdsy3QZAQENagP+IhfQfYYJ7UJeuErmM7ehAYHA3sm5DmYN XoOLHMzhnsZQMNNhgFd6hkAzcvYsBMKsykLb6dE5iwh8U/P9JX8NTo/iZwNshulR PGlkE/rUjQLtRKpCBVJBkYReBCkZxtmcLWnr/5C7nt7pRs97ayxejqsV3QFxdWE7 97xlc/Ldf54= =AVEa -----END PGP SIGNATURE-----