With Microscope and Tweezers: Chronology

With Microscope and Tweezers:

An Analysis of the Internet Virus of November 1988


This is a description of the chronology of the virus, as seen from MIT. It is intended as a description of how one major Internet site discovered and reacted to the virus. This includes the actions of our group at MIT which wound up decompiling the virus and discovering its inner details, and the people across country who were mounting similar efforts. It is our belief that the people involved acted swiftly and effectively during the crisis and deserve many thanks. Also, there is much to be learned from the way events unfolded. Some clear lessons for the future emerged, and as usual, many unresolved and difficult issues have also risen to the forefront to be considered by the networking and computer community.

The events described took place between Wednesday 2 November 1988 and Friday 11 November 1988. All times are stated in eastern standard time.

Wednesday: Genesis

Gene Myers
[ncsc] of the NCSC analyzed the Cornell mailer logs. He found that testing of the sendmail attack first occurred on 19 October 1988 and continued through 28 October 1988. On 29 October 1988, there was an increased level of testing; Gene believes the virus author was attempting to send the binaries over the SMTP connections, an attempt which was bound to fail since the SMTP is only defined for 7 bit ASCII data transfers[smtp]. The author appeared to go back to the drawing board, returning with the ``grappling hook'' program (see section [hook]) on Wednesday 2 November 1988. The virus was tested or launched at 5:01:59pm. The logs show it infecting a second Cornell machine at 5:04pm. This may have been the genesis of the virus, but that is disputed by reports in the New York Times[nyt] in which Paul Graham of Harvard states the virus started on a machine at the MIT AI Lab via remote login from Cornell. Cliff Stoll of Harvard also believes that the virus was started from the MIT AI Lab. At the time this paper was written, nobody has analyzed the infected Cornell machines to determine where the virus would have gone next if they were indeed the first infected machines.

In any case, Paul Flaherty of Stanford reported to the tcp-group@ucsd.edu mailing list on Friday that Stanford was infected at 9:00pm and that it got to ``most of the campus UNIX machines (cf. ~2500 boxes).'' He also reported the virus originated from prep.ai.mit.edu. This is the earliest report of the virus we have seen.

At 9:30pm Wednesday, wombat.mit.edu, a private workstation at MIT Project Athena maintained by Mike Shanzer was infected. It was running a version of sendmail with the debug command turned on. Mike believes that the attack came from prep.ai.mit.edu since he had an account on prep and wombat was listed in his .rhosts, a file which specifies a list of hosts and users on those hosts who may log into an account over the network without supplying a password. Unfortunately the appropriate logs were lost, making the source of the infection uncertain. (The logs on prep were forwarded via syslog, the 4.3BSD UNIX logging package, to another host which was down and by the time anybody looked the wtmp log, which records logins, it was truncated, perhaps deliberately, to some point on Thursday. The lack of logging information and the routine discarding of what old logs did exist hampered investigations.)

Mike Muuss of BRL reported at the NCSC meeting that RAND was also hit at 9:00pm or soon thereafter; Steve Miller of the University of Maryland (UMD) reports the UMD was first hit at 10:54pm; Phil Lapsley of the University of California, Berkeley (UCB) stated that Berkeley was hit at 11:00pm.


Thursday Morning: ``This isn't April First''

More People Notice the Virus
Dave Edwards, of SRI International, said at the NCSC meeting that SRI was hit at midnight. Chuck Cole and Russell Brand of the Lawrence Livermore National Laboratory (LLNL) reported that they were assembling their response team by 2:00am, and John Bruner independently reported spotting the virus on the S1 machines at LLNL about that time.

Pascal Chesnais of the MIT Media Lab was one of the first people at MIT to spot the virus, after 10:00pm Wednesday, but assumed it was just ``a local runaway program''. A group at the Media lab killed the anomalous shell and compilers processes, and all seemed normal. After going for an dinner and ice cream, they figured out that it was a virus and it was coming in via mail. Their response was to shut down network services such as mail and to isolate themselves from the campus network. The MIT Telecommunications Network Group's monitoring information shows the Media Lab gateway first went down at 11:40pm Wednesday, but was back up by 3:00am. At 3:10am Pascal gave the first notice of the virus at MIT, by creating a message of the day on media-lab (see Figure [amtmotd]).

A Virus has been detected on media-lab, we suspect that whole internet is
infected by now.  The virus is spread via mail of all things... So Mail
outside of media-lab will NOT be accepted.  Mail addressed to foreign
hosts will NOT be delivered.  This situation will continue until someone
figures out a way of killing the virus and telling everyone how to 
do it without using email...

--- lacsap Nov 3 1988 03:10am 

Thursday morning's message of the day on media-lab.mit.edu.

False Alarms or Testing?
Pascal later reported that logs on media-lab show several scattered messages, ``ttloop: peer died: No such file or directory'', which frequently occurred just before the virus attacked (see section
[ha]). There were a few every couple of days, several during Wednesday afternoon and many starting at 9:48pm. The logs on media-lab start on 25 October 1988 and entries were made by telnetd on the following dates before the swarm on Wednesday night: Oct 26 15:01:57, Oct 28 11:26:55, Oct 28 17:36:51, Oct 31 16:24:41, Nov 1 16:08:24, Nov 1 18:02:43, Nov 1 18:58:30, Nov 2 12:23:51, and Nov 2 15:21:47.

It is not clear whether these represent early testing of the virus, or if they were just truly accidental premature closings of telnet connections. We assume the latter. With hindsight we can say a telnetd that logged its peer address, even for such error messages, would have been quite useful in tracing the origin and progress of the virus.

E-mail warnings
The first posting mentioning the virus was by Peter Yee of NASA Ames at 2:28am on Wednesday to the tcp-ip@sri-nic.arpa mailing list. Peter stated that UCB, UCSD, LLNL, Stanford, and NASA Ames had been attacked, and described the use of sendmail to pull over the virus binaries, including the x* files which the virus briefly stored in /usr/tmp. The virus was observed sending VAX and Sun binaries, having DES tables built in, and making some use of .rhosts and hosts.equiv files. A phone number at Berkeley was given and Phil Lapsley and Kurt Pires were listed as being knowledgeable about the virus.

At 3:34am Andy Sudduth from Harvard made his anonymous posting to tcp-ip@sri-nic.arpa The posting said that a virus might be loose on the Internet and that there were three steps to take to prevent further transmission. These included not running fingerd or fixing it not to overwrite the stack when reading its arguments from the net, being sure sendmail was compiled without the debug command, and not running rexecd.

Mike Patton, Network Manager for the MIT Laboratory for Computer Science (LCS), was the first to point out to us the peculiarities of this posting. It was made from an Annex terminal server at Aiken Laboratory at Harvard, by telneting to the SMTP port of iris.brown.edu. This is obvious since the message was from ``foo%bar.arpa'' and because the last line of the message was ``qui\177\177\177'', an attempt to get rubout processing out of the Brown SMTP server, a common mistake when faking Internet mail.

Received: by ATHENA.MIT.EDU (5.45/4.7) id AA29119; Sat, 5 Nov 88 05:59:13 EST
Received: from RELAY.CS.NET by SRI-NIC.ARPA with TCP; Fri, 4 Nov 88 23:23:24 PST
Received: from cs.brown.edu by RELAY.CS.NET id aa05627; 3 Nov 88 3:47 EST
Received: from iris.brown.edu (iris.ARPA) by cs.brown.edu (1.2/1.00)
          id AA12595; Thu, 3 Nov 88 03:47:19 est
Received: from  ( with SMTP via tcp/ip
          by iris.brown.edu on Thu, 3 Nov 88 03:34:46 EST

Path of Andy Sudduth's warning message from Harvard to MIT.

It was ironic that this posting did almost no good. Figure [smtptrace] shows the path it took to get to Athena. There was a 20 hour delay before the message escaped from relay.cs.net and got to sri-nic.arpa. Another 6 hours went by before the message was received by athena.mit.edu. Other sites have reported similar delays.

Yet More People Notice the Virus
About 4:00am Thursday Richard Basch of MIT Project Athena noticed a ``text table full'' syslog message from paris.mit.edu, an Athena development machine. Since there was only one message and he was busy doing a project for a digital design lab course, he ignored it.

At 4:51am Chris Hanson of the MIT AI Laboratory reported spotting anomalous telnet traffic to serveral gateways coming from machines at LCS. He noted that the attempts were occurring every one or two seconds and had been happening for several hours.

At 5:58am Thursday morning Keith Bostic of Berkeley made the first bug fix posting. The message went to the tcp-ip@sri-nic.arpa mailing list and the newsgroups comp.bugs.4bsd.ucb-fixes, news.announce, and news.sysadmin. It supplied the ``compile without the debug command'' fix to sendmail (or patch the debug command to a garbage string), as well as the very wise suggestion to rename the UNIX C compiler and loader (cc and ld), which was effective since the virus needed to compile and link itself, and which would be effective at protecting against non-sendmail attacks, whatever those might have turned out to be. It also told people that the virus renamed itself to ``(sh)'' and used temporary files in /usr/tmp named XNNN,vax.o, XNNN,sun3.o, and XNNN,l1.c (where NNN were random numbers, possibly process id's), and suggested that you could identify infected machine by looking for these files. That was somewhat difficult to do in practice, however, since the virus quickly got rid of all of these files. A somewhat better solution was proposed later in the day by, among others, John Kohl of DEC and Project Athena, who suggested doing a cat -v /usr/tmp, thus revealing the raw contents of the directory, including the names of deleted files whose directory slots had not yet been re-used.

The fingerd attack was not even known, much less understood, at this point. Phil Lapsley reported at the NCSC meeting that Ed Wang of Berkeley discovered the fingerd mechanism around 8:00am and sent mail to Mike Karels, but this mail went unread until after the crisis had passed.

At 8:06am Gene Spafford of Purdue forwarded to the nntp-managers@ucbvax.berkeley.edu mailing list Keith Bostic's fixes. Ted Ts'o of MIT Project Athena forwarded this to an internal Project Athena hackers list (watchmakers@athena.mit.edu) at 10:07am. He expressed disbelief (``no, it's not April 1st''), and thought Athena machines were safe. Though no production Athena servers were infected, several private workstations and development machines were, so this proved overly optimistic.

Mark Reinhold, a MIT LCS graduate student, reacted to the virus around 8:00am by powering off some network equipment in LCS. Tim Shepard, also a LCS graduate student, soon joined him. They were hampered by a growing number of people who wanted information about what was happening. Mark and Tim tried to call Peter Yee several times and eventually managed to get through to Phil Lapsley who relayed what was then known about the virus.

At about this time, Richard Basch returned to his workstation (you can only do so much school-work after all) and noticed many duplicates of the ``text table full'' messages from paris and went to investigate. He discovered several suspicious logins from old accounts which should have long ago been purged. The load was intolerably high, and he only managed to get one line out of a netstat command before giving up, but that proved quite interesting. It showed an outgoing rsh connection from paris to fmgc.mit.edu, which is a standalone non-UNIX gateway.

During Thursday morning Ray Hirschfeld spotted the virus on the MIT Math department Sun workstations and shut down the math gateway to the MIT backbone at 10:15am. It remained down until 3:15pm.

Around 11:00am the MIT Statistics Center called Dan Geer, Manager of System Development at Project Athena. One of their Sun workstations, dolphin.mit.edu had been infected via a Project Athena guest account with a weak password, along with the account of a former staff member. This infection had spread to all hosts in the Statistics Center. They had been trying for some time prior to call Dan to eradicate the virus, but the continual reinfection among their local hosts had proved insurmountably baffling.

Keith Bostic sent a second virus fix message to comp.4bsd.ucb-fixes at 11:12am. It suggested using 0xff instead of 0x00 in the binary patch to sendmail. The previous patch, while effective against the current virus, would drop you into debug mode if you sent an empty command line. He also suggested using the UNIX strings command to look in the sendmail binary for the string ``debug''. If it didn't appear at all then your version of sendmail was safe.

About 11:30am Pascal Chesnais requested that the Network Group isolate the Media Lab building and it remained so isolated until Friday at 2:30pm.

Russ Mundy of the Defense Communications Agency reported at the NCSC meeting that the MILNET to ARPANET mailbridges were shut down at 11:30am and remained down until Friday at 11:00am.

In response to complaints from non-UNIX users, Mark Reinhold and Stan Zanarotti, another LCS graduate student, turned on the repeaters at LCS which had been previously powered down and physically disconnected UNIX machines from the network around 11:15am. Tim Shepard reloaded a root partition of one machine from tape (to start with known software), and added a feature to find, a UNIX file system scanner, to report low-level modification times. Working with Jim Fulton of the X Consortium, Tim inspected allspice.lcs.mit.edu; by 1:00pm, they had verified that the virus had not modified any files on allspice and had installed a recompiled sendmail.


Thursday Afternoon: ``This is Bad News''

Word Spreads
By the time Jon Rochlis of the MIT Telecommunications Network Group arrived for work around noon on Thursday 3 November 1988, the Network Group had received messages from MIT Lincoln Laboratory saying they had ``been brought to their knees'' by the virus, from Sergio Heker of the John Von Neumann National Supercomputer Center warning of network problems, and from Kent England of Boston University saying they had cut their external links. The MIT Network Group loathed the thought of severing MIT's external connections and never did throughout the crisis.

At 1:30pm Dan Geer and Jeff Schiller, Manager of the MIT Network and Project Athena Operations Manager, returned to the MIT Statistics Center and were able to get both VAX and Sun binaries from infected machines.

Gene Spafford posted a message at 2:50pm Thursday to a large number of people and mailing lists including nntp-managers@ucbvax.berkeley.edu, which is how we saw it quickly at MIT. It warned that the virus used rsh and looked in hosts.equiv and .rhosts for more hosts to attack.

Around this time the MIT group in E40 (Project Athena and the Telecommunications Network Group) called Milo Medin of NASA and found out much of the above. Many of us had not yet seen the messages. He pointed out that the virus just loved to attack gateways, which were found via the routing tables, and remarked that it must have not been effective at MIT where we run our own C Gateway code on our routers, not UNIX. Milo also said that it seemed to randomly attack network services, swamping them with input. Some daemons that ran on non-standard ports had logged such abnormal input. At the time we thought the virus might be systematically attacking all possible network services exploiting some unknown common flaw. This was not true but it seemed scary at the time. Milo also informed us that DCA had shut down the mailbridges which serve as gateways between the MILNET and the ARPANET. He pointed us to the group at Berkeley and Peter Yee specifically.

It uses finger
At about 6:00pm on Thursday, Ron Hoffmann, of the MIT Telecommunications Network Group, observed the virus attempting to log into a standalone router using the Berkeley remote login protocol; the remote login attempt originated from a machine previously believed immune since it was running a mailer with the debug command turned off. The virus was running under the user name of nobody, and it appeared that it had to be attacking through the finger service, the only network service running under that user name. At that point, we called the group working at Berkeley; they confirmed our suspicions that the virus was spreading through fingerd.

On the surface, it seemed that fingerd was too simple to have a protection bug similar to the one in sendmail; it was a very short program, and the only program it invoked (using the UNIX exec system call) was named using a constant pathname. A check of the modification dates of both /etc/fingerd and /usr/ucb/finger showed that both had been untouched, and both were identical to known good copies located on a read-only filesystem.

Berkeley reported that the attack on finger involved ``shoving some garbage at it'', probably control A's; clearly an overrun buffer wound up corrupting something.

Bill Sommerfeld of Apollo Computer and MIT Project Athena guessed that this bug might involve overwriting the saved program counter in the stack frame; when he looked at the source for fingerd, he found that the buffer it was using was located on the stack; in addition, the program used the C library gets function, which assumes that the buffer it is given is long enough for the line it is about to read. To verify that this was a viable attack, he then went on to write a program which exploited this hole in a benign way. The test virus sent the string ``Bozo!'' back out the network connection.

Miek Rowan and Mike Spitzer also report having discovered the fingerd mechanism at about the same time and forwarded their discovery to Gene Spafford and Keith Bostic, but in the heat of the moment the discovery went unrecognized. Liudvikas Bukys of the University of Rochester posted to the comp.bugs.4bsd newsgroup a detailed description of the fingerd mechanism at 7:21pm. The message also stated that the virus used telnet but perhaps that was only after cracking passwords. In reality it only sometimes used telnet to ``qualify'' a machine for later attack, and only used rsh and rexec to take advantage of passwords it had guessed.

A risks@kl.sri.com digest[risks1] came out at 6:52pm. It included a message from Cliff Stoll which described the spread of the virus on MILNET and suggested that MILNET sites might want to remove themselves from the network. Cliff concluded by saying, ``This is bad news.'' Other messages were from Gene Spafford, Peter Neumann of SRI, and Matt Bishop of Dartmouth. They described the sendmail propagation mechanism.

Thursday Evening: ``With Microscope and Tweezers''

Getting Down To Work
In the office of the Student Information Processing Board (SIPB), Stan Zanarotti and Ted Ts'o had managed to get a VAX binary and core dump from the virus while it was running on a machine at LCS.

Stan and Ted started attacking the virus. Pretty soon they had figured out the xor encoding of the text strings embedded in the program and were manually decoding them. By 9:00pm Ted had written a program to decode all the strings and we had the list of strings used by the program, except for the built-in dictionary which was encoded in a different fashion (by turning on the high order bit of each character).

At the same time they discovered the ip address of ernie.berkeley.edu,, in the program; they proceeded to take apart the virus routine send_message to figure out what it was sending to ernie, how often, and if a handshake was involved. Stan told Jon Rochlis in the MIT Network Group of the SIPB group's progress. The people in E40 called Berkeley and reported the finding of ernie's address. Nobody seemed to have any idea why that was there.

At 9:20pm Gene Spafford created the mailing list phage@purdue.edu. It included all the people he had been mailing virus information to since the morning; more people were to be added during the next few days. This list proved invaluable, since it seemed to have many of the ``right'' people on it and seemed to work in near real time despite all the network outages.

At 10:18pm Keith Bostic made his third bug fix posting. It included new source code for fingerd which used fgets instead of gets and did an exit instead of return. He also included a more general sendmail patch which disabled the debug command completely.

The Media Descends
About this time a camera crew from WNEV-TV Channel 7 (the Boston CBS affiliate) showed up at the office of James D. Bruce, MIT EECS Professor and Vice President for Information Systems. He called Jeff Schiller and headed over to E40. They were both were interviewed and stated that there were 60,000 Internet hosts, along with an estimate of 10% infection rate for the 2,000 hosts at MIT. The infection rate was a pure guess, but seemed reasonable at the time. These numbers were to stick in a way we never anticipated. Some of the press reports were careful to explain the derivation of the numbers they quoted, including how one could extrapolate that as many as 6,000 computers were infected, but many reports were not that good and simply stated things like ``at least 6,000 machines had been hit.''

We were unable to show the TV crew anything ``visual'' caused by the virus, something which eventually became a common media request and disappointment. Instead they settled for people looking at workstations talking ``computer talk.''

The virus was the lead story on the 11:00pm news and was mentioned on National Public Radio as well. We were quite surprised that the real world would pay so much attention. Sound bites were heard on the 2:00am CBS Radio News, and footage shot that evening was shown on the CBS morning news (but by that point we were too busy to watch).

After watching the story on the 11:00pm news we realized it was time to get serious about figuring out the detailed workings of the virus. We all agreed that decompiling was the route to take, though later we also mounted an effort to infect a specially instrumented machine to see the virus in operation. As Jerry Saltzer said in a later message to the Project Athena staff, we undertook a ``wizard-level analysis'' by going over the virus ``with microscope and tweezers.''


Friday: ``Where's Sigourney Weaver?''

Decompiling in Earnest
Tim Shepard joined the group in E40, just before midnight on Thursday. We thought we saw packets going to ernie and replies coming back, though this later proved to be an illusion. Tim had hundreds of megabytes of packet headers gathered Thursday morning from a subnet at LCS which was known to have had infected machines on it. Unfortunately the data was sitting on a machine at LCS, which was still off the network, so Tim decided to go back and look through his data. Within an hour or two, Tim called back to say that he found no unusual traffic to ernie at all. This was our first good confirmation that the ernie packets were a red-herring or at least that they didn't actually wind up being sent.

Serious decompiling began after midnight. Stan and Ted soon left the SIPB office and joined the group working in E40, bringing with them the decoding of the strings and much of the decompiled main module for the virus. Mark Eichin, who had recently spent a lot of time disassembling-assembling some ROMs and thus had recent experience at reverse engineering binaries, took the lead in dividing the project up and assigning parts to people. He had also woke up in late afternoon and was the most prepared for the long night ahead.

At 1:55am Mark discovered the first of the bugs in the virus. A bzero call in if_init was botched. At 2:04am Stan had a version of the main module that compiled. We called Keith Bostic at Berkeley at 2:20am and arranged to do FTP exchanges of source code on an MIT machine (both Berkeley and MIT had never cut their outside network connections). Unfortunately, Keith was unable to get the hackers at Berkeley to take a break and batch up their work, so no exchange happened at that time.

At 2:45am Mark started working on checkother since the Berkeley folks were puzzled by it. Jon Rochlis was working on the later cracksome routines. By 3:06am Ted had figured out that ha built a table of target hosts which had telnet listeners running. By 3:17am Ted and Hal Birkeland from the Media Lab had determined that the crypt routine was the same as one found in the C library. Nobody had yet offered a reason why it was included in the virus, rather than being picked up at link time. Mark had finished checkother and Ted had finished permute at 3:28am. We worked on other routines throughout the morning.

Observations from Running the Virus
The first method of understanding the virus was the decompilation effort. A second method was to watch the virus as it ran, in an attempt to characterize what it was doing -- this is akin to looking at the symptoms of a biological virus, rather than analyzing the DNA of the virus.

We wanted to do several things to prepare for observing the virus:

Mike Muuss reported that the BRL group focused on monitoring the virus in action. They prepared a special logging kernel, but even in coordination with Berkeley were unable to re-infect the machine in question until Saturday.

By 1:00am Friday we had set up the monitoring equipment (an IBM PC running a packet monitor) and two workstations (one acting as the target, the other running a packet monitoring program and saving the packet traces to disk), all separated from the network by a link-layer bridge and had dubbed the whole setup the ``virus net''. We, too, were unsuccessful in our attempt to get our target machine infected until we had enough of the virus decompiled to understand what arguments it wanted. By 3:40am John Kohl had the virus running on our "virus net" and we learned a lot by watching what it did. The virus was soon observed trying telnet, SMTP, and finger connections to all gateways listed in the routing table. Later it was seen trying rsh and rexec into one of the gateways.

At 4:22am, upon hearing of the virus going after yet another host in a ``new'' manner, Jon Rochlis remarked ``This really feels like the movie Aliens. So where is Sigourney Weaver?'' Seeing the virus reach out to infect other machines seemed quite scary and beyond our control.

At 5:45am we called the folks at Berkeley and finally exchanged code. A number of people in Berkeley had punted to get some sleep, and we had a bit of difficulty convincing the person who answered Keith Bostic's phone that we weren't the bad guy trying to fool them. We gave him a number at MIT that showed up in the NIC's whois database, but he never bothered to call back.

At this point a bunch of us went out and brought back some breakfast.

The Media Really Arrives
We had been very fortunate that the press did not distract us, and that we were thus able to put most of our time into our decompilation and analysis efforts. Jim Bruce and the MIT News Office did a first rate job of dealing with most of the press onslaught. By early morning Friday there was so much media interest that MIT News Office scheduled a press conference for noon in the Project Athena Visitor Center in E40.

Just before the press conference, we briefed Jim on our findings and what we thought was important: the virus didn't destroy or even try to destroy any data; it did not appear to be an ``accident;'' we understood enough of the virus to speak with authority; many people (especially the people we had talked to at Berkeley) had helped to solve this.

We were amazed at the size of the press conference -- there were approximately ten TV camera crews and twenty-five reporters. Jeff Schiller spent a good amount of time talking to reporters before the conference proper began, and many got shots of Jeff pointing at the letters ``(sh)'' on the output of a ps command. Jim and Jeff answered questions as the decompiling crew watched from a vantage point in the back of the room. At one point a reporter asked Jeff how many people had enough knowledge to write such a virus and in particular, if Jeff could have written such a program. The answer was of course many people could have written it and yes, Jeff was one of them. The obvious question was then asked: ``Where were you on Wednesday night, Jeff?'' This was received with a great deal of laughter. But when a reporter stated that sources at the Pentagon had said that the instigator of the virus had come forward and was a BU or MIT graduate student, we all gasped and hoped it hadn't really been one of our students.

After the conference the press filmed many of us working (or pretending to work) in front of computers, as well as short interviews.

The media was uniformly disappointed that the virus did nothing even remotely visual. Several also seemed pained that we weren't moments away from World War III, or that there weren't large numbers of companies and banks hooked up to ``MIT's network'' who were going to be really upset when Monday rolled around. But the vast majority of the press seemed to be asking honest questions in an attempt to grapple with the unfamiliar concepts of computers and networks. At the NCSC meeting Mike Muuss said, ``My greatest fear was that of seeing a National Enquirer headline: Computer Virus Escapes to Humans, 96 Killed.'' We were lucky that didn't happen.

Perhaps the funniest thing done by the press was the picture of the virus code printed in Saturday's edition of the Boston Herald[herald]. Jon Kamens of MIT Project Athena had made a window dump of the assembly code for the start of the virus (along with corresponding decompiled C code), even including the window dump command itself. The truly amusing thing was that the Herald had gotten an artist to add tractor feed holes to the printout in an attempt to make it look like something that a computer might have generated. We're sure they would have preferred a dot matrix printer to the laser printer we used.

Keith Bostic called in the middle of the press zoo, but we were too busy dealing with the press, so we cut the conversation short. He called us back around 3:00pm and asked for our affiliations for his next posting. Keith also asked if we liked the idea of posting bug fixes to the virus itself, and we instantly agreed with glee. Keith made his fourth bug fix posting at 5:04pm, this time with fixes to the virus. Again he recommended renaming ld, the UNIX linker.

Things began to wind down after that, though the press was still calling and we managed to put off the NBC Today show until Saturday afternoon. Most of us got a good amount of sleep for the first time in several days.


Saturday: Source Code Policy

Saturday afternoon, 5 November 1988, the Today show came to the SIPB Office, which they referred to as the ``computer support club'' (sic), to find a group of hackers. They interviewed Mark Eichin and Jon Rochlis and used Mark's description of what hackers really try to do on Monday morning's show.

After the Today show crew left, many of us caught up on our mail. It was then that we first saw Andy Sudduth's Thursday morning posting to tcp-ip@sri-nic.arpa and Mike Patton stopped by and pointed out how strange it was.

We soon found ourselves in the middle of a heated discussion on phage@purdue.edu regarding distribution of the decompiled virus source code. Since we had received several private requests for our work, we sat back and talked about what to do, and quickly reached consensus. We agreed with most of the other groups around the country who had come to the decision not to release the source code they had reverse engineered. We felt strongly that the details of the inner workings of the virus should not be kept hidden, but that actual source code was a different matter. We (and others) intended to write about the algorithms used by the virus so that people would learn what the Internet community was up against. This meant that somebody could use those algorithms to write a new virus; but the knowledge required to do so is much greater than what is necessary to recompile the source code with a new, destructive line or two in it. The energy barrier for this is simply too low. The people on our team (not the MIT administration) decided to keep our source private until things calmed down; then we would consider to whom to distribute the program. A public posting of the MIT code was not going to happen.

Jerry Saltzer, among others, has argued forcefully that the code itself should be publicly released at some point in the future. After sites have had enough time to fix the holes with vendor supplied bug fixes, we might do so.

Tuesday: The NCSC Meeting

On Tuesday 8 November 1988 Mark Eichin and Jon Rochlis attended the Baltimore post-mortem meeting hosted by the NCSC. We heard about the meeting indirectly at 2:00am and flew to Baltimore at 7:00am. Figuring there was no time to waste with silly things like sleep, we worked on drafts of this document. The meeting will be described in more detail by the NCSC, but we will present a very brief summary here.

Attending the meeting were representatives of the National Institute of Science and Technology (NIST), formerly the National Bureau of Standards, the Defense Communications Agency (DCA) , the Defense Advanced Research Projects Agency (DARPA), the Department of Energy (DOE), the Ballistics Research Laboratory (BRL), the Lawrence Livermore National Laboratory (LLNL), the Central Intelligence Agency (CIA), the University of California Berkeley (UCB), the Massachusetts Institute of Technology (MIT), Harvard University, SRI International, the Federal Bureau of Investigation (FBI), and of course the National Computer Security Center (NCSC). This is not a complete list. The lack of any vendor participation was notable.

Three-quarters of the day was spent discussing what had happened from the different perspectives of those attending. This included chronologies, actions taken, and an analysis of the detailed workings of the virus; Meanwhile our very rough draft was duplicated and handed out.

The remaining time was spent discussing what we learned from the attack and what should be done to prepare for future attacks. This was much harder and it is not clear that feasible solutions emerged, though there was much agreement on several motherhood and apple-pie suggestions. By this we mean the recommendations sound good and and by themselves are not objectionable, but we doubt they will be effective.

Wednesday-Friday: The Purdue Incident

On Wednesday evening 9 November 1988, Rich Kulawiec of Purdue posted to phage@purdue.edu that he was making available the unas disassembler that he (and others at Purdue) used to disassemble the virus. He also made available the output of running the virus through this program. Rumor spread and soon the NCSC called several people at Purdue, including Gene Spafford, in an attempt to get this copy of the virus removed. Eventually the President of Purdue was called and the file was deleted. The New York Times ran a heavily slanted story about the incident on Friday 11 November 1988

Several mistakes were made here. First the NCSC was concerned about the wrong thing. The disassembled virus was not important and was trivial for any infected site to generate. It simply was not anywhere near as important as the decompiled virus, which could have very easily have been compiled and run. When the MIT group was indirectly informed about this and discovered exactly what was publicly available, we wondered what the big deal was. Secondly, the NCSC acted in a strong-handed manner that upset the people at Purdue who got pushed around.

Other similar incidents occurred around the same time. Jean Diaz of the MIT SIPB, fowarded a partially decompiled copy of the virus to phage@purdue.edu at some time on Friday 4 November 1988, but it spent several days in a mail queue on hplabs.hp.com before surfacing. Thus it had been posted before any of the discussion of source code release had occurred. It also was very incomplete and thus posed little danger since the effort required to turn it into a working virus was akin to the effort required to write the virus from scratch.

These two incidents, however, caused the press to think that a second outbreak of the virus had once again brought the network to its knees. Robert French, of the MIT SIPB and Project Athena, took one such call on Thursday 10 November and informed the reporter that no such outbreak had occurred. Apparently rumors of source code availability (the Purdue incident and Jean's posting) led to the erroneous conclusion that enough information of some sort had been let out and damage had been done. Rumor control was once again shown to be important.