*********************************************************************** DDN Security Bulletin 9105 DCA DDN Defense Communications System 22 APR 91 Published by: DDN Security Coordination Center (SCC@NIC.DDN.MIL) (800) 235-3155 DEFENSE DATA NETWORK SECURITY BULLETIN The DDN SECURITY BULLETIN is distributed by the DDN SCC (Security Coordination Center) under DCA contract as a means of communicating information on network and host security exposures, fixes, & concerns to security & management personnel at DDN facilities. Back issues may be obtained via FTP (or Kermit) from NIC.DDN.MIL [192.67.67.20] using login="anonymous" and password="guest". The bulletin pathname is SCC:DDN-SECURITY-yynn (where "yy" is the year the bulletin is issued and "nn" is a bulletin number, e.g. SCC:DDN-SECURITY-9001). ********************************************************************** ALERT REGARDING MASQUERADING ACTIVITIES + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + ! ! ! The following important advisory was issued by the Computer ! ! Emergency Response Team (CERT) and is being relayed unedited ! ! via the Defense Communications Agency's Security Coordination ! ! Center distribution system as a means of providing DDN ! ! subscribers with useful security information. ! ! ! + - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - + SCC NOTE: The practice referred to in the following advisory as "Social Engineering" is perhaps better known as "Masquerading." CA-91:04 CERT Advisory April 18, 1991 Social Engineering --------------------------------------------------------------------------- DESCRIPTION: The Computer Emergency Response Team/Coordination Center (CERT/CC) has received several incident reports concerning users receiving requests to take an action that results in the capturing of their password. The request could come in the form of an e-mail message, a broadcast, or a telephone call. The latest ploy instructs the user to run a "test" program, previously installed by the intruder, which will prompt the user for his or her password. When the user executes the program, the user's name and password are e-mailed to a remote site. We are including an example message at the end of this advisory. These messages can appear to be from a site administrator or root. In reality, they may have been sent by an individual at a remote site, who is trying to gain access or additional access to the local machine via the user's account. While this advisory may seem very trivial to some experienced users, the fact remains that MANY users have fallen for these tricks (refer to CERT Advisory CA-91:03). IMPACT: An intruder can gain access to a system through the unauthorized use of the (possibly privileged) accounts whose passwords have been compromised. This problem could affect all systems, not just UNIX systems or systems on the Internet. SOLUTION: The CERT/CC recommends the following actions: 1) Any users receiving such a request should verify its authenticity with their system administrator before acting on the instructions within the message. If a user has received this type of request and actually entered a password, he/she should immediately change his/her password to a new one and alert the system administrator. 2) System administrators should check with their user communities to ensure that no user has followed the instructions in such a message. Further, the system should be carefully examined for damage or changes that the intruder may have caused. We also ask that you contact the CERT/CC. 3) The CERT/CC urges system administrators to educate their users so that they will not fall prey to such tricks. --------------------------------------------------------------------------- SAMPLE MESSAGE as received by the CERT (including spelling errors, etc.) OmniCore is experimenting in online - high resolution graphics display on the UNIX BSD 4.3 system and it's derivitaves. But, we need you're help in testing our new product - TurboTetris. So, if you are not to busy, please try out the ttetris game in your machine's /tmp directory. just type: /tmp/ttetris Because of the graphics handling and screen-reinitialazation, you will be prompted to log on again. Please do so, and use your real password. Thanks you for your support. You'll be hearing from us soon! OmniCore END OF SAMPLE MESSAGE --------------------------------------------------------------------------- If you believe that your system has been compromised, contact CERT/CC via telephone or e-mail. Computer Emergency Response Team/Coordination Center (CERT/CC) Software Engineering Institute Carnegie Mellon University Pittsburgh, PA 15213-3890 Internet E-mail: cert@cert.sei.cmu.edu Telephone: 412-268-7090 24-hour hotline: CERT/CC personnel answer 7:30a.m.-6:00p.m. EST, on call for emergencies during other hours. Past advisories and other computer security related information are available for anonymous ftp from the cert.sei.cmu.edu (128.237.253.5) system.