Advanced persistent threat
An advanced persistent threat is a stealthy computer network threat actor, typically a nation state or state-sponsored group, which gains unauthorized access to a computer network and remains undetected for an extended period. In recent times, the term may also refer to non-state sponsored groups conducting large-scale targeted intrusions for specific goals.
Such threat actors' motivations are typically political or economic. Every major business sector has recorded instances of attacks by advanced actors with specific goals seeking to steal, spy, or disrupt. These sectors include government, defense, financial services, legal services, industrial, telecoms, consumer goods and many more. Some groups utilize traditional espionage vectors, including social engineering, human intelligence and infiltration to gain access to a physical location to enable network attacks. The purpose of these attacks is to install custom malicious software.
The median "dwell-time", the time an APT attack goes undetected, differs widely between regions. FireEye reports the mean dwell-time for 2018 in the Americas is 71 days, EMEA is 177 days and APAC is 204 days. This allows attackers a significant amount of time to go through the attack cycle, propagate and achieve their objective.
Definition
Definitions of precisely what an APT is can vary, but can be summarized by their named requirements below:- Advanced – Operators behind the threat have a full spectrum of intelligence-gathering techniques at their disposal. These may include commercial and open source computer intrusion technologies and techniques, but may also extend to include the intelligence apparatus of a state. While individual components of the attack may not be considered particularly "advanced", their operators can typically access and develop more advanced tools as required. They often combine multiple targeting methods, tools, and techniques in order to reach and compromise their target and maintain access to it. Operators may also demonstrate a deliberate focus on operational security that differentiates them from "less advanced" threats.
- Persistent – Operators have specific objectives, rather than opportunistically seeking information for financial or other gain. This distinction implies that the attackers are guided by external entities. The targeting is conducted through continuous monitoring and interaction in order to achieve the defined objectives. It does not mean a barrage of constant attacks and malware updates. In fact, a "low-and-slow" approach is usually more successful. If the operator loses access to their target they usually will reattempt access, and most often, successfully. One of the operator's goals is to maintain long-term access to the target, in contrast to threats who only need access to execute a specific task.
- Threat – APTs are a threat because they have both capability and intent. APT attacks are executed by coordinated human actions, rather than by mindless and automated pieces of code. The operators have a specific objective and are skilled, motivated, organized and well funded. Actors are not limited to state sponsored groups.
Criteria
- Objectives – The end goal of your threat, your adversary.
- Timeliness – The time spent probing and accessing your systems.
- Resources – The level of knowledge and tools used in the event.
- Risk tolerance – The extent the threat will go to remain undetected.
- Skills and methods – The tools and techniques used throughout the event.
- Actions – The precise actions of a threat or numerous threats.
- Attack origination points – The number of points where the event originated.
- Numbers involved in the attack – How many internal and external systems were involved in the event, and how many peoples systems have different influence/importance weights.
- Knowledge source – The ability to discern any information regarding any of the specific threats through online information gathering.
History and targets
The Stuxnet computer worm, which targeted the computer hardware of Iran's nuclear program, is one example. In this case, the Iranian government might consider the Stuxnet creators to be an advanced persistent threat.
Within the computer security community, and increasingly within the media, the term is almost always used in reference to a long-term pattern of sophisticated computer network exploitation aimed at governments, companies, and political activists, and by extension, also to ascribe the A, P and T attributes to the groups behind these attacks. Advanced persistent threat as a term may be shifting focus to computer-based hacking due to the rising number of occurrences. PC World reported an 81 percent increase from 2010 to 2011 of particularly advanced targeted computer attacks.
Actors in many countries have used cyberspace as a means to gather intelligence on individuals and groups of individuals of interest. The United States Cyber Command is tasked with coordinating the US military's offensive and defensive cyber operations.
Numerous sources have alleged that some APT groups are affiliated with, or are agents of, governments of sovereign states.
Businesses holding a large quantity of personally identifiable information are at high risk of being targeted by advanced persistent threats, including:
- Higher education
- Financial institutions
- Energy
- Transportation
- Technology
- Health care
- Telecommunications
- Manufacturing
- Agriculture
Life cycle
Actors behind advanced persistent threats create a growing and changing risk to organizations' financial assets, intellectual property, and reputation by following a continuous process or kill chain:- Target specific organizations for a singular objective
- Attempt to gain a foothold in the environment
- Use the compromised systems as access into the target network
- Deploy additional tools that help fulfill the attack objective
- Cover tracks to maintain access for future initiatives
In 2013, Mandiant presented results of their research on alleged Chinese attacks using APT method between 2004 and 2013 that followed similar lifecycle:
- Initial compromise – performed by use of social engineering and spear phishing, over email, using zero-day viruses. Another popular infection method was planting malware on a website that the victim's employees will be likely to visit.
- Establish foothold – plant remote administration software in victim's network, create net backdoors and tunnels allowing stealth access to its infrastructure.
- Escalate privileges – use exploits and password cracking to acquire administrator privileges over victim's computer and possibly expand it to Windows domain administrator accounts.
- Internal reconnaissance – collect information on surrounding infrastructure, trust relationships, Windows domain structure.
- Move laterally – expand control to other workstations, servers and infrastructure elements and perform data harvesting on them.
- Maintain presence – ensure continued control over access channels and credentials acquired in previous steps.
- Complete mission – exfiltrate stolen data from victim's network.
Previous reports from Secdev had previously discovered and implicated Chinese actors.
Mitigation strategies
There are tens of millions of malware variations, which makes it extremely challenging to protect organizations from APT. While APT activities are stealthy and hard to detect, the command and control network traffic associated with APT can be detected at the network layer level with sophisticated methods. Deep log analyses and log correlation from various sources is of limited usefulness in detecting APT activities. It is challenging to separate noises from legitimate traffic. Traditional security technology and methods have been ineffective in detecting or mitigating APTs. Active cyber defense has yielded greater efficacy in detecting and prosecuting APTs when applying cyber threat intelligence to hunt and adversary pursuit activities.APT groups
China
- PLA Unit 61398
- PLA Unit 61486
- Buckeye
- Red Apollo
- Codoso Team
- Wocao
- PLA Unit 78020
- Periscope Group
- Double Dragon
- Tropic Trooper
- Winnti Group
- Numbered Panda
Iran
- Elfin Team
- Helix Kitten
- Charming Kitten
- APT39
Israel
- Unit 8200
- XM Cyber
North Korea
- Ricochet Chollima
- Lazarus Group
Russia
- Fancy Bear
- Cozy Bear
- Voodoo Bear
- Venomous Bear
United States
- Equation Group
Uzbekistan
- SandCat
Vietnam
- OceanLotus