RiskPundit

While the term, Advanced Persistent Threat (APT) is not a new term, it is being used much more often since the breach announcement Google made in January. I wrote about it here and here.

Mandiant, a security consulting firm, defines the APT "as a group of sophisticated, determined and coordinated attackers that have been systematically compromising U.S. government and commercial computer networks for years. The vast majority of APT activity observed by MANDIANT has been linked to China." You can read more about what they have to say here.

Mandiant did a webinar on February 18 called Malware Behaving Badly, in which they compared Mass Malware Threats to Advanced Persistent Threats. As of today, Feb 20, Mandiant has not posted the webinar on its site.

Richard Bejtlich defined APT in this January 16, 2010 blog post:

• Advanced means the adversary can operate in the full
  spectrum of computer intrusion. They can use the most pedestrian
  publicly available exploit against a well-known vulnerability, or they
  can elevate their game to research new vulnerabilities and develop
  custom exploits, depending on the target's posture.




• Persistent
  means the adversary is formally tasked to accomplish a mission. They
  are not opportunistic intruders. Like an intelligence unit they receive
  directives and work to satisfy their masters. Persistent does not
  necessarily mean they need to constantly execute malicious code on
  victim computers. Rather, they maintain the level of interaction needed
  to execute their objectives.




• Threat means the
  adversary is not a piece of mindless code. This point is crucial. Some
  people throw around the term "threat" with reference to malware. If
  malware had no human attached to it (someone to control the victim,
  read the stolen data, etc.), then most malware would be of little worry
  (as long as it didn't degrade or deny data). Rather, the adversary here
  is a threat because it is organized and funded and motivated. Some
  people speak of multiple "groups" consisting of dedicated "crews" with
  various missions.

Bejtlich goes on to itemize APT objectives, which interestingly does not include stealing money:

• Political objectives that include continuing to suppress its own population in the name of "stability."




• Economic objectives
  that rely on stealing intellectual property from victims. Such IP can
  be cloned and sold, studied and underbid in competitive dealings, or
  fused with local research to produce new products and services more
  cheaply than the victims.




• Technical objectives that
  further their ability to accomplish their mission. These include
  gaining access to source code for further exploit development, or
  learning how defenses work in order to better evade or disrupt them.
  Most worringly is the thought that intruders could make changes to
  improve their position and weaken the victim.




• Military objectives that include identifying weaknesses that allow inferior military forces to defeat superior military forces. The Report on Chinese Government Sponsored Cyber Activities addresses issues like these.

Mike Cloppert, a security engineer at Lockheed Martin, wrote about APTs in mid-2009 in his Security Intelligence series of blog posts. In Security Intelligence: Introduction (pt 1), he defines APT as "any sophisticated adversary engaged in information warfare in support of long-term strategic goals." Note his focus on the adversary and goals rather than just the techniques.

In summary then, APTs do represent techniques that are more difficult to detect because the adversary, when faced with an above average defense, does not move on to a weaker target. The adversary is persistent and will escalate tactics. Second the focus is on stealing intellectual property rather than money to advance the adversary's strategic  technical, economic, political, and military goals.