Good worms back on the agenda

But are good viruses possible?


ARLINGTON, Virginia - A researcher has reopened the subject of beneficial worms, arguing that the capabilities of self-spreading code could perform better penetration testing inside networks, turning vulnerable systems into distributed scanners.

The worms, dubbed nematodes after the parasitic worm used to kill pests in gardens, could give security administrators the ability to scan machines inside a corporate network but beyond a local subnet, David Aitel, principal researcher of security firm Immunity, said at the Black Hat Federal conference.

"Rather than buy a scanning system for every segment of your network, you can use nematodes to turn every host into a scanner," he said during an interview with SecurityFocus. "You'll be able to see into the shadow organisation of a network - you find worms on machines and you don't know how they got there."

The topic of whether self-propagating code can have a good use has cropped up occasionally among researchers in the security community. In 1994, a paper written by antivirus researcher Vesselin Bontchev concluded that 'good' viruses are possible, but the safeguards and limitations on the programs would mean that the resulting code would not resemble what most people considered a virus.

Later attempts at creating 'good' worms have failed, however, mainly because the writers have not adopted many of the safeguards outlined in the Bontchev paper. The Welchia worm - a variant of the MSBlast, or Blaster, worm - had apparently been created to fix the vulnerability exploited by the MSBlast worm, but had serious programming errors that caused the program to scan so aggressively for new hosts, it effectively shut down many corporate networks.

Immunity's research is the latest attempt to create a more rigorously conceived framework for creating worms that could spread across specific networks to find and report vulnerabilities. The research essentially offers two advances, a strategy for the controlled propagation of worms and a framework in which reliable worms could be created quickly, Aitel said.

"History has repeatedly shown us that people who write worms by hand make mistakes," he said. "Worms are difficult to build and very difficult to test."

The nematode worms would have to get permission to spread by querying a central server for a specific digital token, which Aitel dubbed a nematoken, before spreading to a particular machine. Another version of the software would use a whitelist to spread among only the company's computers.

Because the worms would be limited to spreading in a specific company's network, they would be completely legal, said Aitel. He noted that penetration testers today are given the right by a company to exploit systems on that company's networks. The distributed nature of the worms do make ascertaining permission more difficult, he acknowledged.

Aitel's idea is a new twist on an old concept. An author using the name MidNyte wrote a response to Bontchev's paper in 1999 arguing that a 'good' virus that kept information on the last 100 hosts to which it spread could help defend against bad viruses.

However, Aitel also argues that, in today's complex networks, nematodes could significantly reduce the cost of scanning a large network, by bringing the advantages of peer-to-peer concepts to penetration testing and network scanning. Rather than buying a new sensor for each subnet in a company, the nematode could spread using existing pathways to enumerate any computers with a given set of vulnerabilities. Moreover, the technology could be used to move search agents across a network to find specific files or to push intelligence to all desktops without a specific client.

On the other hand, the dangers inherent in self-propagating code are hard to overcome, said Jose Nazario, senior security and software engineer for network defense firm Arbor Networks.

"I still have my doubts that the controls he described are effective enough," Nazario said. "He addressed how you shut the nematodes down and how you make sure they don't infect other networks, but he hasn't addressed machine instability and the danger when people carry laptops across network boundaries."

Nazario, the author of Defense and Detection Strategies Against Internet Worms, believes the best way to find vulnerabilities on a large network is to use dedicated sensors, an approach used by Arbor Networks.

"There are a number of ways of finding those vulnerabilities in the network without the inherent risks involved in self-propagating code," he said.

This article originally appeared in SecurityFocus

Copyright © 2006, SecurityFocus


Other stories you might like

  • Experts: AI should be recognized as inventors in patent law
    Plus: Police release deepfake of murdered teen in cold case, and more

    In-brief Governments around the world should pass intellectual property laws that grant rights to AI systems, two academics at the University of New South Wales in Australia argued.

    Alexandra George, and Toby Walsh, professors of law and AI, respectively, believe failing to recognize machines as inventors could have long-lasting impacts on economies and societies. 

    "If courts and governments decide that AI-made inventions cannot be patented, the implications could be huge," they wrote in a comment article published in Nature. "Funders and businesses would be less incentivized to pursue useful research using AI inventors when a return on their investment could be limited. Society could miss out on the development of worthwhile and life-saving inventions."

    Continue reading
  • Declassified and released: More secret files on US govt's emergency doomsday powers
    Nuke incoming? Quick break out the plans for rationing, censorship, property seizures, and more

    More papers describing the orders and messages the US President can issue in the event of apocalyptic crises, such as a devastating nuclear attack, have been declassified and released for all to see.

    These government files are part of a larger collection of records that discuss the nature, reach, and use of secret Presidential Emergency Action Documents: these are executive orders, announcements, and statements to Congress that are all ready to sign and send out as soon as a doomsday scenario occurs. PEADs are supposed to give America's commander-in-chief immediate extraordinary powers to overcome extraordinary events.

    PEADs have never been declassified or revealed before. They remain hush-hush, and their exact details are not publicly known.

    Continue reading
  • Stolen university credentials up for sale by Russian crooks, FBI warns
    Forget dark-web souks, thousands of these are already being traded on public bazaars

    Russian crooks are selling network credentials and virtual private network access for a "multitude" of US universities and colleges on criminal marketplaces, according to the FBI.

    According to a warning issued on Thursday, these stolen credentials sell for thousands of dollars on both dark web and public internet forums, and could lead to subsequent cyberattacks against individual employees or the schools themselves.

    "The exposure of usernames and passwords can lead to brute force credential stuffing computer network attacks, whereby attackers attempt logins across various internet sites or exploit them for subsequent cyber attacks as criminal actors take advantage of users recycling the same credentials across multiple accounts, internet sites, and services," the Feds' alert [PDF] said.

    Continue reading

Biting the hand that feeds IT © 1998–2022