From: CERT Advisory <cert-advisory@cert.org> Subject: CERT Advisory CA-99.01 - TCP.Wrappers Date: Thu, 21 Jan 1999 21:08:48 -0500 To: cert-advisory@coal.cert.org Reply-To: cert-advisory-request@cert.org -----BEGIN PGP SIGNED MESSAGE----- CERT Advisory CA-99-01-Trojan-TCP-Wrappers Original issue date: January 21, 1999 Topic: Trojan horse version of TCP Wrappers _________________________________________________________________ The CERT Coordination Center has received confirmation that some copies of the source code for the TCP Wrappers tool (tcpd) were modified by an intruder and contain a Trojan horse. We strongly encourage sites running the TCP Wrappers tool to immediately verify the integrity of their distribution. _________________________________________________________________ I. Description TCP Wrappers is a tool commonly used on Unix systems to monitor and filter connections to network services. The CERT Coordination Center has received confirmation that some copies of the file tcp_wrappers_7.6.tar.gz have been modified by an intruder and contain a Trojan horse. This file contains the source code for TCP Wrappers version 7.6. This Trojan horse appears to have been made available on a number of FTP servers since Thursday, January 21, 1999 at 06:16:00 GMT. The Trojan horse version of TCP Wrappers provides root access to intruders on port 421. Additionally, upon compilation, this Trojan horse version sends email to an external address. This email includes information identifying the site and the account that compiled the program. Specifically, the program sends information obtained from running the commands 'whoami' and 'uname -a'. II. Impact An intruder can gain unauthorized root access to any host running this Trojan horse version of TCP Wrappers. Note: If you have already installed a Trojan horse version of TCP Wrappers, intruders can identify your site using information contained in this advisory. Please read the "Solution" section and take appropriate action to protect your site as soon as possible. III. Solution We encourage sites to verify the authenticity of their TCP Wrapper distribution, regardless of where it was obtained. You can use the following MD5 checksums to verify the integrity of the TCP Wrappers file: File: tcp_wrappers_7.6.tar.gz Correct version: size 99438 MD5 e6fa25f71226d090f34de3f6b122fb5a Trojan Horse version: size 99186 MD5 af7f76fb9960a95a1341c1777b48f1df Note that it is not sufficient to rely on the timestamps of the file when trying to determine if you have a copy of the Trojan horse version. Additionally, the file tcp_wrappers_7.6.tar.gz is distributed with the detached PGP signature tcp_wrappers_7.6.tar.gz.sig. Wietse Venema is the author and maintainer of the TCP Wrappers distribution.You can verify the integrity and authenticity of your distribution with Wietse Venema's PGP public key. We have included a copy of his PGP public key below. Note that the Trojan horse version was not signed, and that Wietse Venema's PGP key was not compromised in any way. We have verified that the distribution of TCP Wrappers offered by the CERT Coordination Center at ftp.cert.org was not involved in this activity. TCP Wrappers is available from our FTP site at ftp://ftp.cert.org/pub/tools/tcp_wrappers/tcp_wrappers_7.6.tar.gz MD5 checksum: e6fa25f71226d090f34de3f6b122fb5a As with any port, if you are not using port 421, we encourage you to filter it at your network perimeter. 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______________________________________________________________________ CERT/CC Contact Information Email: cert@cert.org Phone: +1 412-268-7090 (24-hour hotline) Fax: +1 412-268-6989 Postal address: CERT Coordination Center Software Engineering Institute Carnegie Mellon University Pittsburgh PA 15213-3890 U.S.A. CERT personnel answer the hotline 08:00-20:00 EST(GMT-5) / EDT(GMT-4) Monday through Friday; they are on call for emergencies during other hours, on U.S. holidays, and on weekends. Using encryption We strongly urge you to encrypt sensitive information sent by email. Our public PGP key is available from http://www.cert.org/CERT_PGP.key. If you prefer to use DES, please call the CERT hotline for more information. Getting security information CERT publications and other security information are available from our web site http://www.cert.org/. To be added to our mailing list for advisories and bulletins, send email to cert-advisory-request@cert.org and include SUBSCRIBE your-email-address in the subject of your message. Copyright 1998 Carnegie Mellon University. Conditions for use, disclaimers, and sponsorship information can be found in http://www.cert.org/legal_stuff.html. * CERT is registered in the U.S. Patent and Trademark Office ______________________________________________________________________ NO WARRANTY Any material furnished by Carnegie Mellon University and the Software Engineering Institute is furnished on an "as is" basis. Carnegie Mellon University makes no warranties of any kind, either expressed or implied as to any matter including, but not limited to, warranty of fitness for a particular purpose or merchantability, exclusivity or results obtained from use of the material. Carnegie Mellon University does not make any warranty of any kind with respect to freedom from patent, trademark, or copyright infringement. _________________________________________________________________ Revision History -----BEGIN PGP SIGNATURE----- Version: 2.6.2 iQCVAwUBNqfS1XVP+x0t4w7BAQEtXgQAjMvSXAYlEezp1yQ5sMex4+dYpeEgsBW6 c57PBexeBDwXMR6sE14JDfoZl9wjuN2EZ1KCYoV4UvVk1uXjVli6Epa2D3SR68Xv WJr40X/LptEXQnzCmWstqxOmsqZkSkFWxUF+C4Qxm7jcbNe1qpAoam/VoPcMTtZb ln9e861vkxI= =Px6D -----END PGP SIGNATURE-----
CERT outputs advisory on TCP Wrappers
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