Published: 01/10/2021

Advanced Persistent Threat (APT)

What is advanced persistent threat (APT)?

Advanced Persistent Threat (APT) is a term used to describe certain cyberattacks of a particularly persistent nature, where attackers are extremely difficult to eliminate. All the victims in these APT attack scenarios were previously subjected to infiltration and malware implantation stages (which may last for months or even years), before any actual data exfiltration occurs. Because of this, when it comes to APT intrusions, there is never any direct evidence that can be easily found by traditional investigation activities such as examining system logs and network traffic. This makes dealing with an APT attack especially frustrating and complicated for investigators and incident response teams alike.

Advanced persistent threats vs traditional attacks

One of the characteristics which make Advanced Persistent Threats so different from traditional attacks is the fact that they are performed over a long period of time. Attackers will use this extended timeframe to study their target and plan ahead for days, weeks or sometimes even months – making sure to leave as little evidence behind as possible at each step along the way.

Many APT campaigns also go after only a couple of very specific targets rather than attempting to spread out their activities over many victims. This makes them much more difficult to handle because instead of having lots of machines affected by an intrusion attempt at any given time, you may have only one particular machine attacked repeatedly with malware implants being reapplied several times before data theft occurs.

The fact that most APT intrusions go after only one or a handful of specific victims and leave very few traces behind makes them perfect tools for use in espionage activities – especially when it comes to targeted attacks against government agencies, embassies and large corporations.

How an APT attack works

First of all, attackers need to gather as much information about their target as possible. Using traditional scanning techniques and tools is definitely out of the question here because it would be detected immediately. Instead, attackers will typically use automated tools with an exploit/vulnerability module or even a malware implant installer file – making sure to keep all activity hidden from detection by hiding the process behind several layers of obfuscation.

Once they have infiltrated your network covertly, attackers may deploy bots to start sending larger amounts of stolen data back to their servers where it can be collected and used for further criminal activities or simply sold off on the black market for quick financial gain.

In addition to this, many attackers who perform APT operations will also try to undermine or tamper with internal company operations. By doing this, they will create an environment of confusion and misinformation which makes it extremely difficult for the incident response team to figure out what is really going on at all times.

The motives behind APT attacks

The most common motive behind APT attacks is information gathering followed by data exfiltration. Attackers use APT techniques in order to stay in a network long enough to either gather sensitive information or implant malware which can be used for sending out even larger amounts of data later on when attackers decide it’s time for them to make their move.

In addition, many APT attackers seek not only financial gain but also access to classified/sensitive data. This may include data related to military operations or simply be targeted at individuals who have access to trade secrets, money transfers or other sensitive information.

Steps to take to protect yourself from an APT attack

The best way to protect yourself from APT attacks is to keep your computers up-to-date and fully patched. If they are not, attackers will most likely be able to compromise the system using a known exploit for unpatched software or simply target a critical vulnerability which has yet to be patched by administrators. Also, training your employees and making them aware of security threats is crucial so that they do their part in keeping company information safe as well.

Finally, it’s important to remove all suspicious files and programs from your systems as soon as possible because this may prevent even more damage from occurring down the road, such as data theft or infiltration into additional computers once the threat actor(s) find out about existing backdoors left behind during the initial operation.

As mentioned above, using traditional defensive techniques against APT attackers isn’t very likely to produce good results which is why you need to use security solutions that can detect and remove all types of attacks while also providing you with the information needed in order to act fast against these kinds of threats.

Ways to recover if you’ve been hacked with an APT attack

In case you have been targeted by an APT attack, there are a few things that you will need to do in order to recover from the incident properly. This includes:

  • Removing all malware infections which may be present on your systems
  • Blocking any communication between your computers and malicious servers or domains using web filtering or email security solutions
  • Doing your best to determine how the attacker entered your network (e.g. looking for weak passwords, misconfigured services, etc.) – this may give you important clues as to where they are located at the moment
  • Conducting a thorough investigation of all compromised machines with help from trained professionals if possible
  • Resetting administrative accounts (especially those used for remote access purposes)
  • Restoring all affected files from a backup that was made before the operations began

Frequently asked questions about advanced persistent threats

What is the difference between APT and other types of attacks?

Since there are many different kinds of malware and ransomware which can be used to attack computers on a global scale, APTs stand out because they tend to use more sophisticated techniques in order to gain access to information on company networks. In addition, attackers may also try deleting logs and cleaning up their tracks after compromising a system so that it’s harder for security teams to see what they’ve done afterwards.

What kind of damage can an APT cause?

Since most organizations lack the proper expertise when it comes to detecting and removing hackers who perform APT operations, this often leads to data breaches and stolen confidential documents which can result in serious consequences such as:

  • Loss of money if customer records or other financial information is stolen
  • Damage to a company’s reputation which may result in loss of clientele
  • Unfair competitive advantage for rival companies who learn about your business via APT attacks

How can ransomware be used as an advanced persistent threat?

In some instances, attackers have been known to use ransomware on computers that they want to gain remote access to. This allows them to encrypt all data and hold it hostage until the ransom has been paid. In addition, the more time goes by after the initial compromise of a machine, the harder it will be for security teams to detect their presence by looking at logs and other tools.

What are ways of distinguishing advanced threats from normal ones?

Some red flags you should look for when detecting advanced attacks include:

  • Actions which are uncharacteristic or unusual for employees (e.g. accessing data in unusual ways, sending large amounts of data to addresses outside the company’s network, etc.)
  • Large amounts of traffic between computers on your network and foreign servers that are not related to regular business operations
  • Unusual connections via Remote Desktop Protocol or VNC may indicate that adversaries are using these services in order to gain access to targeted systems
  • Systems with high CPU/RAM usage which cannot be attributed to any legitimate processes

Schedule Your Demo

Tired of your website being exploited by malicious malware and bots?

We can help

Subscribe and stay updated

Insightful articles, data-driven research, and more cyber security focussed content to your inbox every week.


By registering, you confirm that you agree to Netacea's privacy policy.