Advanced Persistent Threat
Cyber-attacks have become much more sophisticated over the years. So much so that a new term has emerged: advanced persistent threat (APT). An APT is group of individuals that have both the means and the intent to launch persistent attacks against specific targets. Understanding these groups and their behavior is important when evaluating threats against any organization. Their methods are relevant for anyone studying for either Security+ or SSCP exams.
APTs are often sponsored by foreign governments, and they often launch attacks against other governments for espionage purposes. However, APTs can launch attacks against any organization.
An Advanced Persistent Threat Gathers Data
Imagine if a group of people had an unlimited amount of money and time, and they were tasked with exploiting as many government computers as they could in Arlington, Virginia, outside of Washington DC.
IP addresses are issued geographically, so it’s a rather simple matter to discover what IP addresses are issued in Arlington. ICMP sweep (or host enumeration sweep) tools can help identify which IP addresses are actually operational, similar to how a ping can identify if a system is up. Many firewalls block ICMP sweeps so if it fails, it doesn’t necessarily mean that the host is not operational. However, if it succeeds, it certainly verifies it is operational. Other tools such as Geobytes can help them get additional public information about the IP address.
The APT can then use port scanning tools such as Nmap or Nessus to get additional information on each IP address. If a port is open, it provides insight into what services and protocols are running on a system. For example, if port 25 is open, the Simple Mail Transport Protocol (SMTP) is running on the system.
Many port scanning tools can also send special types of packets to the server and analyze the responses to gain additional information on the system. For example, a Christmas tree packet (identified as an Xmas attack in the SY0-301 Security+ exam) takes advantage of the fact that different operating systems respond to protocols with slight modifications. These scans can often identify the operating system, and the version of the system.
For example, Cisco IOS and Windows systems respond differently to different types of queries. In some cases, the attacker can use these tools to also identify applications. If port 25 is open, it indicates that SMTP is running and additional queries can identify if it’s an email server. In many cases, it’s possible to identify the email application such as if it’s a Microsoft Exchange server, and even what version of Microsoft Exchange it’s using.
They record all this information into a database. In some cases, the APT may be to exploit vulnerabilities in systems they find. In other cases, all they’re able to do is collect and record the data. And wait for an opportunity.
An Advanced Persistent Threat Looks for Vulnerabilities
Other parts of the APT focus on identifying vulnerabilities, and exploiting them. For example, if an exploit is discovered in Microsoft Exchange, the APT searches the database to locate servers hosting Microsoft Exchange. They can then launch the attack and exploit the servers in their database. Similarly, if an exploit is discovered on web servers, they search their database and launch this attack on the web servers in their target area.
This describes how one part of an APT may be focused on government computers in Arlington. However, another team may be focused on government computers in Washington, DC, another in New York, another in Atlanta, and on and on. Similarly, teams can focus on specific organizations such as Google.com, Amazon.com, or any other company that may have information of interest.
These attackers are always present and always searching for vulnerabilities. An organization can be vigilant with security 99 percent of the time, but if they let their guard down for just a short time, the APT is ready to exploit it. Among other things, this also helps to understand the importance of a defense in depth practice. Even if a vulnerability exists in one area (such as on the mail server), other protections help prevent the attacker from getting any further.
Advanced Persistent Threat Summary
If you’re working in the IT field, and especially if you’re studying for a security certification, it’s important to understand an advanced persistent threat. The attackers aren’t bored teenagers randomly attacking computers on the Internet. They are much more sophisticated.
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