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Monday, 22 October 2012

Cyber Security Part II - Botnets, APT's & AET's

This is the second of a five part series focusing on Cyber Security.  This article will examine some of the key terms and components that comprise of a cyber attack in 2012.  I'll take a look at the individual 'lone wolf' style attacks, right through to the complex networks of robots, capable of distributing malware on a vast scale.  I'll also quickly examine the components of an Advanced Persistent Attack and the increasing rise of Advanced Evasion Techniques, being used by malware to avoid detection.

From Lone Wolf to Botnets

The Lone WolfIn any walk of life the lone wolf is seen to be independent, agile and potentially unpredictable.  Whilst these characteristics are often seen to be difficult to defend against in a cyber security landscape, being an individual can have it's limitations.  In the new dawn of the internet era (yes I know, what was that like?) in the early 90's, the appearance of individual hackers was often portrayed as glamorous and cool.  The script-kiddy style attacker was generally male, 18-23 years old and a self-badged nerd/geek/social outsider.  Their main motive for attacking online systems was simply for prestige and credibility, driving for acceptance of their technical aptitude.


Today, there has been a significant movement to a more targeted and explicitly aggressive type of lone wolf attacker.  The evolution from script-kiddy to lamer, to cracker and fully fledged hacker has been swift, with tooling, training and support easily available on line.  Their main motives tend to political (hacktivist) or for automated income, aiming to harvest and sell identity or banking data from individuals.  If income is the driver, the relative safety, anonymity and low investment costs often make on line crime more effective than 'street' style criminality.


Botnets - Robot networks are large scale and complex attack systems.  Often controlled by organised criminals, a botnet contains several different components.  The network itself, is controlled by a 'bot-herder', which in turn manages several command and control (C&C) centres. These C&C's then help to remotely manage the bots.  The bots are simply infected machines on the internet, belonging to everyday users, unaware their machine is infected.  These bots then combine, to perform an attack, generally either of a denial of service style, utilising the large processing power available to them, or a data harvesting exercise, often collecting personal information such as identity or social security data.

The botnet owners, often have the ability to create their own bespoke malware, which can be distributed online via email attachments, infected URL's (masked via phishing attacks, or more latterly altered QR links) or other USB drops.  The botnets are increasingly becoming more 'professionalised' and sophisticated, adapting to new technologies (Twitter has been used as a command channel, with encoded tweets used to contain C&C messages).  The main driver is cash.  Automated income supplies are often the end goal, which again, compared to street crime is often less risky and more rewarding.

APT's to AET's

Advanced Persistent Threats - APT's as the name suggests, are advanced targeted pieces of cyber attack software, often developed by large scale organisations or even nation states.  APT's generally contain several different pieces of highly optimised components, joined together to perform denial of service or data harvesting attacks.  A botnet could be involved in helping to execute the components.  APT's often have a specific target, with recent attacks being focused on SCADA style industrial control system and critical infrastructures (Stuxnet, Duqu).  The APT will contain an initial payload distributed via social engineering techniques, USB drops, email and infected URL's.  Once the initialiser code is distributed, other secondary components such as access escalation tools, data harvesters and propagators are often used to complete the attack.  Code is often self replicating and modifying, making detection and removal difficult.  As a result, the true impact of some of the more complex APT's is unknown.


Advanced Evasion Techniques - AET's are not themselves malware of pieces or specific attack software.  The evasion technique is a relatively new term, used to describe how malware payloads are now using new approaches to avoid detection by next generation firewalls (NGFW's) and intrusion detection systems (IDS's).  AET's help to obfuscate the underlying malware code, that helps to evade the often signature based approach to checking inbound network traffic.  There are several new tools on the market place, that can help to test the underlying network security devices for any potential vulnerabilities in the ability to prevent malware bypassing perimeter security.  Whilst not all traffic using an AET will be malware, it's another tool that is being used in the pursuit of malware distribution.

Research by security firm Stonesoft, identified 147 possible atomic evasion techniques.  When thinking that techniques could be combined, that is a staggering array of new vectors that could be exploited.  Many of the techniques involve using unusual or rarely used protocol properties or design flaws with regards to device memory or configuration.

As the number of services, users and online ecommerce transactions increase, so too will the sophistication and professionalism of attackers and the software and techniques they use.

@SimonMoffatt