Category Archives: Forensics

What we can learn from the Therac-25

What does Nancy Leveson’s classic analysis of the Therac-25 recommend? (“An Investigation of the Therac-25 Accidents,” by Nancy Leveson, University of Washington and Clark S. Turner, University of California, Irvine, IEEE Computer, Vol. 26, No. 7, July 1993, pp. 18-41.)
“Inadequate Investigation or Followup on Accident Reports. Every company building safety-critical systems should have audit trails and analysis procedures that are applied whenever any hint of a problem is found that might lead to an accident.” p. 47

“Government Oversight and Standards. Once the FDA got involved in the Therac-25, their response was impressive, especially considering how little experience they had with similar problems in computer-controlled medical devices. Since the Therac-25 events, the FDA has moved to improve the reporting system and to augment their procedures and guidelines to include software. The input and pressure from the user group was also important in getting the machine fixed and provides an important lesson to users in other industries.” pp. 48-49

The lesson being that you have to have built-in audit, reporting, transparency, and user visibility for reputation.

Which is exactly what Dennis Quaid is asking for.

Remember, most of those 99,000 deaths a year from medical errors aren’t due to control of complicated therapy equipment: Continue reading

Data, Reputation, and Certification Against Spam

I’m giving a talk today at the Internet2 workshop on Collaborative Data-Driven Security for High Performance Networks at WUSTL, St. Louis, MO. You can follow along with the PDF.

There may be some twittering on #DDCSW.

-jsq

Medical Metrics Considered Overrated

One of the presenters at Metricon 5.0 was comparing IT security to other fields in various aspects of metrics and monitoring. I mentioned I thought she was giving far too much green for good to the field of medicine. This provoked repeated back and forth later.

My point was that 150 years after the invention of epidemiology and 100 years after the discovery of bacterial transmission of disease, in medicine application of known preventive measures is so low that Atul Gawande of Harvard has gotten large (on the order of 30%) reductions in deaths from complications of surgery in many hospitals simply by getting them to use checklists for things like washing hands before surgery.

I have an elderly relative in a nursing home who can’t take pills whole due to some damage to nerves in her neck. Again and again visitors sent by the family discover nursing home staff trying to give her pills whole without grinding them up. Why? They don’t read instructions about her, and previous shifts don’t remind later shifts. This kind of communication problem is epidemic not only in nursing homes but in hospitals. I found my father in a diabetic coma because nurses hadn’t paid any attention to him being a diabetic and needing to eat frequently. Fortunately, a bit of honey brought him out of it. Even nurses readily acknowledge this problem, but it persists. I can rattle off many other examples.

To which someone responded, yes, but medicine has epidemiology, and Edward Tufte demonstrated in one of his books that that goes well beyond checklists in to actual analysis, as in a physician’s discovery of a well in London being he source of cholera. I responded, yes, John Snow, in 1854: that was the first thing I said when I stood up to address this. But who now applies what he learned? One-shot longitudinal studies are not the same as ongoing monitoring with comparable metrics to show how well one group is doing compared to both the known science and to other groups.

Many people still didn’t get it, and kept referring to checklists as rudimentary.

So I tried again. If John Snow were alive today, he wouldn’t be prescribing statins for life to people with high blood pressure. He would be compiling data on who has high blood pressure and what they have been doing and eating before they got it. He would follow this evidence back to discover that one of the main contributors to high blood pressure, heart disease, and diabetes in the U.S. is high fructose corn syrup (HFCS). Then he would mount a political campaign to ban high fructose corn syrup, which would be the modern equivalent of his removal of the handle from the pump of the well that stopped the cholera.

To which someone replied, but there are political forces who would oppose that. And I said, yes, of course. Permit me to elaborate.

There were political forces in John Snow’s time, too, and he dealt with them:

Dr Snow took a sample of water from the pump, and, on examining it under a microscope, found that it contained “white, flocculent particles.” By 7 September, he was convinced that these were the source of infection, and he took his findings to the Board of Guardians of St James’s Parish, in whose parish the pump fell.

Though they were reluctant to believe him, they agreed to remove the pump handle as an experiment. When they did so, the spread of cholera dramatically stopped. [actually the outbreak had already lessened for several days]

Snow also investigated several outliers, all of which turned out to involve people actually travelling to the Soho well to get water.
Still no one believed Snow. A report by the Board of Health a few months later dismissed his “suggestions” that “the real cause of whatever was peculiar in the case lay in the general use of one particular well, situate [sic] at Broad Street in the middle of the district, and having (it was imagined) its waters contaminated by the rice-water evacuations of cholera patients. After careful inquiry,” the report concluded, “we see no reason to adopt this belief.”

So what had caused the cholera outbreak? The Reverend Henry Whitehead, vicar of St Luke’s church, Berwick Street, believed that it had been caused by divine intervention, and he undertook his own report on the epidemic in order to prove his point. However, his findings merely confirmed what Snow had claimed, a fact that he was honest enough to own up to. Furthermore, Whitehead helped Snow to isolate a single probable cause of the whole infection: just before the Soho epidemic had occurred, a child living at number 40 Broad Street had been taken ill with cholera symptoms, and its nappies had been steeped in water which was subsequently tipped into a leaking cesspool situated only three feet from the Broad Street well.

Whitehead’s findings were published in The Builder a year later, along with a report on living conditions in Soho, undertaken by the magazine itself. They found that no improvements at all had been made during the intervening year. “Even in Broad-street it would appear that little has since been done… In St Anne’s-Place, and St Anne’s-Court, the open cesspools are still to be seen; in the court, so far as we could learn, no change has been made; so that here, in spite of the late numerous deaths, we have all the materials for a fresh epidemic… In some [houses] the water-butts were in deep cellars, close to the undrained cesspool… The overcrowding appears to increase…” The Builder went on to recommend “the immediate abandonment and clearing away of all cesspools — not the disguise of them, but their complete removal.”

Nothing much was done about it. Soho was to remain a dangerous place for some time to come.

John Snow didn’t shy away from politics. He was successful in getting the local politicians to agree to his first experiment, which was successful in helping end that outbreak of cholera. He even drew his biggest opponent into doing research, which ended up confirming Snow’s epidemiological diagnosis and extending it further to find the original probable source of infection of the well. But even that didn’t suffice for motivating enough political will to fix the problem.

From which I draw two conclusions:

  1. Even John Snow is over-rated. Sure, he found the problem, but he didn’t get it fixed longterm.

  2. Why not? Because that would require ongoing monitoring of likely sources of infection (which sort of happened) compared to actual incidents of disease (which does not appear to have happened), together with eliminating the known likely sources.
Eliminating likely known sources is what Dr. Gawande’s checklist is about, 150 years later, which was my original point. And the ongoing monitoring and comparisons appear not to be happening, even yet.

As someone at Metricon said, who will watch the watchers? I responded, yes, that’s it!

One-shot longitudinal studies can create great information. That’s what John Snow did. That’s what much of scientific experiment is about. But even when you repeat the experiment to confirm it, that’s not the same as ongoing monitoring. And it’s not the same as checklists to ensure application of what was learned in the experiment.

What is really needed is longitudinal experiments combined checklists, plus ongoing monitoring, plus new analysis derived from the monitoring data. That’s at least four levels. All of them are needed. Modern medicine often only manages the first. And in the case of high fructose corn syrup (HFCS), until recently even the first was lacking, and most of the experiments that have happened until very recently have not come from the country with the biggest HFCS health problem, namely the U.S. A third of the entire U.S. population is obese, and another third is overweight, with concomittant epidemics of heart disease, diabetes, and high blood pressure. And the medical profession prescribes statins for life instead of getting to the root of the problem and fixing it.

Yes, I think the field of medicine gets rated too much green for good.

And if IT security wants to improve its own act, it also needs all four levels, not just the first or the second.

-jsq

Route Hijacking: Identity Theft of Internet Infrastructure

Peter Svensson gives an old and quite serious problem some mainstream press in this AP story from 8 May 2010:
On April 25, 1997, millions of people in North America lost access to all of the Internet for about an hour. The hijacking was caused by an employee misprogramming a router, a computer that directs data traffic, at a small Internet service provider.

A similar incident happened elsewhere the next year, and the one after that. Routing errors also blocked Internet access in different parts of the world, often for millions of people, in 2001, 2004, 2005, 2006, 2008 and 2009. Last month a Chinese Internet service provider halted access from around the world to a vast number of sites, including Dell.com and CNN.com, for about 20 minutes.

In 2008, Pakistan Telecom tried to comply with a government order to prevent access to YouTube from the country and intentionally “black-holed” requests for YouTube videos from Pakistani Internet users. But it also accidentally told the international carrier upstream from it that “I’m the best route to YouTube, so send all YouTube traffic to me.” The upstream carrier accepted the routing message, and passed it along to other carriers across the world, which started sending all requests for YouTube videos to Pakistan Telecom. Soon, even Internet users in the U.S. were deprived of videos of singing cats and skateboarding dogs for a few hours.

In 2004, the flaw was put to malicious use when someone got a computer in Malaysia to tell Internet service providers that it was part of Yahoo Inc. A flood of spam was sent out, appearing to come from Yahoo.

The Pakistani incident is illustrated in the accompanying story and video by RIPE.

This problem has been known for a long time. Why hasn’t it been fixed? Continue reading

FireEye’s Ozdok Botnet Takedown Observed

FireEye coordinated a takedown of botnet Ozdok or MegaD, on 5-6 Nov 2009, with cooperation by many ISPs and DNS registrars.

Good show! What effects did it have on spam? Not just spam from this botnet; spam in general.

Botnets and spam volume

This graph was presented at NANOG 48, Austin, TX, 24 Feb 2010, in FireEye’s Ozdok Botnet Takedown In Spam Blocklists and Volume Observed by IIAR Project, CREC, UT Austin. John S. Quarterman, Quarterman Creations, Prof. Andrew Whinston, PI CREC, UT Austin. That was a snapshot of an ongoing project, Incentives, Insurance and Audited Reputation: An Economic Approach to Controlling Spam (IIAR).

That presentation was enough to demonstrate the main point: takedowns are good, but we need a lot more of them and a lot more coordinated if we are to make a real dent in spam.

The IIAR project will keep drilling down in the data and building up models. One goal is to build a reputation system to show how effective takedowns and other anti-spam measures are, on which ASNs.

Thanks especially to CBL and to Team Cymru for very useful data, and to FireEye for a successful takedown.

We’re all ears for further takedowns to examine.

-jsq

CCTV Security Fad Fails

CCTV2_228x342.jpg London probably has more security cameras per square inch than any other city, and:
The billions of pounds spent covering Britain with CCTV cameras has been an “utter fiasco” and failed to slash crime, Scotland Yard’s surveillance chief has said.

Detective Chief Inspector Mick Neville said a Metropolitan Police pilot project found just three per cent of street robberies in London were solved using CCTV images.

He claimed the vast swathes of money spent on cameras had been wasted because criminals don’t fear the cameras.

Billions spent on CCTV have failed to cut crime and led to an ‘utter fiasco’, says Scotland Yard surveillance chief, Just 3% of street robberies in London solved, By DANIEL BATES, Daily Mail, Last updated at 13:48pm on 6th May 2008

Needless to say, there are numerous efforts planned to make the cameras pay anyway.

The basic problem is:

But Mr Neville also castigated the police and claimed officers can’t be bothered to seek out CCTV images because it’s “hard work”.
CCTV is not the only security fad that hasn’t panned out:
For every 800 DNA samples being added by the police – including those taken from innocent people – only one crime is being solved.
We’ll see if either of these white elephant programs get terminated. I’m not holding my breath.

-jsq

Phishing Verified

jeremy_clarkson.jpg Or is it really phishing when the victim first broadcasts his bank account details?
BTop Gear presenter Jeremy Clarkson has admitted he was wrong to brand the scandal of lost CDs containing the personal data of millions of Britons a “storm in a teacup” after falling victim to an internet scam.

The outspoken star printed his bank details in a newspaper to try and make the point that his money would be safe and that the spectre of identity theft was a sham.

He also gave instructions on how to find his address on the electoral roll and details about the car he drives.

However, in a rare moment of humility Clarkson has now revealed the stunt backfired and his details were used to set up a £500 direct debit payable from his account to the British Diabetic Association.

The charity is one of many organisations that do not need a signature to set up a direct debit.

Clarkson stung by fraud stunt, Guardian Unlimited, Monday January 7 2008

He admits he was wrong, but nonetheless tries to pin the blame partly on a privacy law:
“The bank cannot find out who did this because of the Data Protection Act and they cannot stop it from happening again,” he said. “I was wrong and I have been punished for my mistake.”
At least he doesn’t call for revoking that Act; he does call for going after the perpetrators.

-jsq

PS: Seen on BoingBoing.

Fingerprint False Positives

fingerprint_definition.jpg Not all that glitters is gold:
“Fingerprints, before DNA, were always considered the gold standard of forensic science, and it’s turning out that there’s a lot more tin in that field than gold,” he said. “The public needs to understand that. This judge is declaring, not to mix my metaphors, that the emperor has no clothes.”

Judge bars use of partial prints in murder trial, By Jennifer McMenamin, Sun Reporter, October 23, 2007

The judge did this because of the partial fingerprint false positive linking an Oregon lawyer to the Madrid bombings. Apparently that was only one of twenty false matches in that case. So the judge in this homicide case has ruled that partial fingerprint matches can’t be used as evidence.
At a pretrial hearing in May, prosecutors argued that fingerprint evidence has been accepted by the courts and relied upon for nearly 100 years. Defense attorneys countered that there is no similar history of subjecting the evidence to scientific review.

“The state is correct that fingerprint evidence has been used in criminal cases for almost a century,” Souder, the judge, wrote in her decision. “While that fact is worthy of consideration, it does not prove reliability. For many centuries, perhaps for millennia, humans thought that the earth was flat.”

So if a hundred year old “gold” standard of evidence turns out to be tin, what about all the wide-scan wiretap dragnet evidence that certain governments seem intent on compiling these days?

-jsq

PS: Seen on Bruce Schneier’s blog.

Web Panopticons: China and U.S.

panopticon.gif Fergie points out a university project investigating censorship:

The "Great Firewall of China," used by the government of the People’s Republic of China to block users from reaching content it finds objectionable, is actually a "panopticon" that encourages self-censorship through the perception that users are being watched, rather than a true firewall, according to researchers at UC Davis and the University of New Mexico.

The researchers are developing an automated tool, called ConceptDoppler, to act as a weather report on changes in Internet censorship in China. ConceptDoppler uses mathematical techniques to cluster words by meaning and identify keywords that are likely to be blacklisted.

University Researchers Analyze China’s Internet Censorship System, News Report, Government Technology News, Sep 11, 2007

So the Great Firewall of China watches what users are doing by actively intercepting their traffic. Meanwhile, back in the U.S. of A., how about a passive web panopticon?

Continue reading

Non-Asymmetric Malware

<~~T.A.Z~~>

Most exploits through the Internet have been relatively small guys (individuals, gangs, etc.) against big companies and governments. Yet they’re already using botnets to leverage their activity. What happens when botnets start connecting with other botnets via wireless?

Consider the following scenarios:

  • malware infected PCs actually opening a WiFi connection in a port-knocking nature to the wireless botnet master only
  • no need for wardriving, as malware authors would quickly map the entire WiFi vulnerable population around a given region in the age of malware geolocating IPs using commercial services
  • once a PC gets infected inside an organization, it can automatically turn into a wardriving zombie exposing vulnerable WiFi connections within
  • Bluetooth scanning plugins expose even more vulnerable Bluetooth-enabled devices in the range of the infected host

Distributed WiFi Scanning Through Malware, by Dancho Danchev, @ Friday, August 24, 2007

It already wasn’t clear which side the asymmetry favored, since the bad guys use the full leverage of the Internet and the defenders mostly don’t. Now the bad guys can leverage the leverage of the Internet by also using local wireless connections to further interconnect.

Did we need more proof that there’s no such thing as a perimeter to fortify anymore?

-jsq