At the same time, Oberman revised his anti-WANK program for DOE. By Monday night US Eastern Standard Time, Oberman was able to send out an early copy of a vaccine designed to protect computers which hadn't been infected yet, along with an electronic warning about the worm. His first electronic warning, distributed by CIAC, said in part: THE COMPUTER INCIDENT ADVISORY CAPABILITY C I A C ADVISORY NOTICE The W.COM Worm affecting VAX VMS Systems October 16, 1989 18:37 PSTNumber A-2 This is a mean bug to kill and could have done a lot of damage. Since it notifies (by mail) someone of each successful penetration and leaves a trapdoor (the FIELD account), just killing the bug is not adequate. You must go in and make sure all accounts have passwords and that the passwords are not the same as the account name. R. Kevin Oberman Advisory Notice A worm is attacking NASA's SPAN network via VAX/VMS systems connected to DECnet. It is unclear if the spread of the worm has been checked. It may spread to other systems such as DOE's HEPNET within a few days. VMS system managers should prepare now. The worm targets VMS machines, and can only be propagated via DECnet. The worm exploits two features of DECnet/VMS in order to propagate itself. The first is the default DECnet account, which is a facility for users who don't have a specific login ID for a machine to have some degree of anonymous access. It uses the default DECnet account to copy itself to a machine, and then uses the `TASK 0' feature of DECnet to invoke the remote copy. It has several other features including a brute force attack. Once the worm has successfully penetrated your system it will infect .COM files and create new security vulnerabilities. It then seems to broadcast these vulnerabilities to the outside world. It may also damage files as well, either unintentionally or otherwise. An analysis of the worm appears below and is provided by R. Kevin Oberman of Lawrence Livermore National Laboratory. Included with the analysis is a DCL program that will block the current version of the worm. At least two versions of this worm exist and more may be created. This program should give you enough time to close up obvious security holes. A more thorough DCL program is being written. If your site could be affected please call CIAC for more details... Report on the W.COM worm. R. Kevin Oberman Engineering Department Lawrence Livermore National Laboratory October 16, 1989 The following describes the action of the W.COM worm (currently based on the examination of the first two incarnations). The replication technique causes the code to be modified slightly which indicates the source of the attack and learned information. All analysis was done with more haste than I care for, but I believe I have all of the basic facts correct. First a description of the program: